Search Results

Search found 19141 results on 766 pages for 'double free'.

Page 147/766 | < Previous Page | 143 144 145 146 147 148 149 150 151 152 153 154  | Next Page >

• How To Start Your Own Professional Blog with WordPress

  - by Matthew Guay

  Would you like to start your own blog or website?  With a free WordPress  account, it’s free and easy to get started creating your own professional quality blog site. This is the first part in a series on how to create your own professional quality blog site. No, we’re not talking about some cheapo looking blog from Blogger or something on Facebook, but creating a quality blog you can be proud of and present to millions of readers online. WordPress is one of the most popular blogging platforms, powering hundreds of high-profile websites and blogs around the world.  It’s both powerful and easy to use, which makes it great whether you’re just starting out or are a blogging pro.  To start out with your blogging project WordPress is completely free, and you can use the online interface or install the WordPress software on your own server and blog from there. Getting Started You can start a blog in just a few minutes.  Head over to WordPress.com and click Sign up now on the right-hand side of the main page. Enter a username and password, check that you agree with the legal terms, select the “Gimme a blog” bullet, and click Next. WordPress may inform you that your username is already taken, simply choose a new one and try again. Next, choose a domain for your blog.  This will be the address for your site, and cannot be changed, so be sure to choose exactly what you want.  If you’d prefer your address to be yourname.com instead of yourname.wordpress.com, you can add your own domain for a fee after your blog is setup…but we’ll cover that later. Once you click signup, you will be sent a confirmation email.  While you wait for the email to arrive you can go ahead and enter in your name and a short bio about yourself. When you receive your confirmation email, click the link.  Congratulations; you now have your own blog! You can view your new blog immediately, though the default theme isn’t very interesting without your content and pictures. Back on the page you opened from the email, click Login to access your blog’s administration page and to start adding stuff to your blog.  You can also access your blog’s admin page anytime by from yourname.wordpress.com/admin, substituting your own blog name for yourname. Enter your username and password, then click Log in to get started. Adding Content to your WordPress.com Blog When you sign in to your WordPress blog, you’ll first see the WordPress Admin page.  Here you can see recent posts and comments, and you can see stats of how many people have visited your site.  You can also access all of your blog tools and settings right from this page. To add a new post to your blog, click the Posts link on the left, then click “Add New” either on the left menu or on the top of the Edit Posts page.  Or, if you want to edit the default first post, hover over it and select Edit. Or click the New Posts button on the top of the page.  This menu bar is always visible whenever you’re logged in, so it’s an easy way to add a post. The editor lets you easily write anything you want in a Microsoft Word-style editor.  You can format your text, add lists, links, quotes, and more.  When you’re ready to share your content with the world, click Publish on the right side. To add pictures or other files, click the picture icon beside “Upload/Insert”.  Your free blog account can store up to 3Gb of pictures and documents which will definitely give you a good start. Click Select Files, and then choose the pictures or documents you want to add to your post. When the pictures have uploaded, you can add a caption and choose how to position the picture.  When you’re finished, select “Insert into Post”.   Or, if you want to add a video, click the video button.  You have to add a paid upgrade to upload videos directly, but you can add YouTube and other online videos for free. Click the “From URL” tab, and then paste the link to the YouTube video and click Insert into post. If you’re a code geek, click the HTML tab in the editor and edit the HTML of your blog post the geeky way. Once you’ve added all your content and edited it the way you want, click the Publish button on the right of the editor.  Or, you can click Preview to make sure it looks right, and then click Publish. Here’s our blog with the new blog post containing a picture and video.  While you’re getting to know you’re way around the controls in WordPress, the Preview feature will be your best friend while you try to organize the content to your liking.   Conclusion It only takes a couple minutes to get started blogging at WordPress.com. Whether you want to write about your daily life, share pictures of your children, or review the latest books and gadgets, WordPress.com is a great place to get started for free.  But we’ve only covered a small portion of the WordPress features…but this should get you started. Check back for more WordPress and blogging coverage coming up soon! Links Signup for a free WordPress.com account Similar Articles Productive Geek Tips Add Social Bookmarking (Digg This!) Links to your Wordpress BlogHow-To Geek SoftwareProtecting Your WordPress Admin Panel From Hackers With .htaccessMake a Backup Copy of your Production Wordpress Blog on UbuntuLinux QuickTip: Downloading and Un-tarring in One Step TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Awe inspiring, inter-galactic theme (Win 7) Case Study – How to Optimize Popular Wordpress Sites Restore Hidden Updates in Windows 7 & Vista Iceland an Insurance Job? Find Downloads and Add-ins for Outlook Recycle !

  Read the article

• Enabling Kerberos Authentication for Reporting Services

  - by robcarrol

  Recently, I’ve helped several customers with Kerberos authentication problems with Reporting Services and Analysis Services, so I’ve decided to write this blog post and pull together some useful resources in one place (there are 2 whitepapers in particular that I found invaluable configuring Kerberos authentication, and these can be found in the references section at the bottom of this post). In most of these cases, the problem has manifested itself with the Login failed for User ‘NT Authority\Anonymous’ (“double-hop”) error. By default, Reporting Services uses Windows Integrated Authentication, which includes the Kerberos and NTLM protocols for network authentication. Additionally, Windows Integrated Authentication includes the negotiate security header, which prompts the client to select Kerberos or NTLM for authentication. The client can access reports which have the appropriate permissions by using Kerberos for authentication. Servers that use Kerberos authentication can impersonate those clients and use their security context to access network resources. You can configure Reporting Services to use both Kerberos and NTLM authentication; however this may lead to a failure to authenticate. With negotiate, if Kerberos cannot be used, the authentication method will default to NTLM. When negotiate is enabled, the Kerberos protocol is always used except when: Clients/servers that are involved in the authentication process cannot use Kerberos. The client does not provide the information necessary to use Kerberos. An in-depth discussion of Kerberos authentication is beyond the scope of this post, however when users execute reports that are configured to use Windows Integrated Authentication, their logon credentials are passed from the report server to the server hosting the data source. Delegation needs to be set on the report server and Service Principle Names (SPNs) set for the relevant services. When a user processes a report, the request must go through a Web server on its way to a database server for processing. Kerberos authentication enables the Web server to request a service ticket from the domain controller; impersonate the client when passing the request to the database server; and then restrict the request based on the user’s permissions. Each time a server is required to pass the request to another server, the same process must be used. Kerberos authentication is supported in both native and SharePoint integrated mode, but I’ll focus on native mode for the purpose of this post (I’ll explain configuring SharePoint integrated mode and Kerberos authentication in a future post). Configuring Kerberos avoids the authentication failures due to double-hop issues. These double-hop errors occur when a users windows domain credentials can’t be passed to another server to complete the user’s request. In the case of my customers, users were executing Reporting Services reports that were configured to query Analysis Services cubes on a separate machine using Windows Integrated security. The double-hop issue occurs as NTLM credentials are valid for only one network hop, subsequent hops result in anonymous authentication. The client attempts to connect to the report server by making a request from a browser (or some other application), and the connection process begins with authentication. With NTLM authentication, client credentials are presented to Computer 2. However Computer 2 can’t use the same credentials to access Computer 3 (so we get the Anonymous login error). To access Computer 3 it is necessary to configure the connection string with stored credentials, which is what a number of customers I have worked with have done to workaround the double-hop authentication error. However, to get the benefits of Windows Integrated security, a better solution is to enable Kerberos authentication. Again, the connection process begins with authentication. With Kerberos authentication, the client and the server must demonstrate to one another that they are genuine, at which point authentication is successful and a secure client/server session is established. In the illustration above, the tiers represent the following: Client tier (computer 1): The client computer from which an application makes a request. Middle tier (computer 2): The Web server or farm where the client’s request is directed. Both the SharePoint and Reporting Services server(s) comprise the middle tier (but we’re only concentrating on native deployments just now). Back end tier (computer 3): The Database/Analysis Services server/Cluster where the requested data is stored. In order to enable Kerberos authentication for Reporting Services it’s necessary to configure the relevant SPNs, configure trust for delegation for server accounts, configure Kerberos with full delegation and configure the authentication types for Reporting Services. Service Principle Names (SPNs) are unique identifiers for services and identify the account’s type of service. If an SPN is not configured for a service, a client account will be unable to authenticate to the servers using Kerberos. You need to be a domain administrator to add an SPN, which can be added using the SetSPN utility. For Reporting Services in native mode, the following SPNs need to be registered --SQL Server Service SETSPN -S mssqlsvc/servername:1433 Domain\SQL For named instances, or if the default instance is running under a different port, then the specific port number should be used. --Reporting Services Service SETSPN -S http/servername Domain\SSRS SETSPN -S http/servername.domain.com Domain\SSRS The SPN should be set for the NETBIOS name of the server and the FQDN. If you access the reports using a host header or DNS alias, then that should also be registered SETSPN -S http/www.reports.com Domain\SSRS --Analysis Services Service SETSPN -S msolapsvc.3/servername Domain\SSAS Next, you need to configure trust for delegation, which refers to enabling a computer to impersonate an authenticated user to services on another computer: Location Description Client 1. The requesting application must support the Kerberos authentication protocol. 2. The user account making the request must be configured on the domain controller. Confirm that the following option is not selected: Account is sensitive and cannot be delegated. Servers 1. The service accounts must be trusted for delegation on the domain controller. 2. The service accounts must have SPNs registered on the domain controller. If the service account is a domain user account, the domain administrator must register the SPNs. In Active Directory Users and Computers, verify that the domain user accounts used to access reports have been configured for delegation (the ‘Account is sensitive and cannot be delegated’ option should not be selected): We then need to configure the Reporting Services service account and computer to use Kerberos with full delegation:   We also need to do the same for the SQL Server or Analysis Services service accounts and computers (depending on what type of data source you are connecting to in your reports). Finally, and this is the part that sometimes gets over-looked, we need to configure the authentication type correctly for reporting services to use Kerberos authentication. This is configured in the Authentication section of the RSReportServer.config file on the report server. <Authentication> <AuthenticationTypes>           <RSWindowsNegotiate/> </AuthenticationTypes> <EnableAuthPersistence>true</EnableAuthPersistence> </Authentication> This will enable Kerberos authentication for Internet Explorer. For other browsers, see the link below. The report server instance must be restarted for these changes to take effect. Once these changes have been made, all that’s left to do is test to make sure Kerberos authentication is working properly by running a report from report manager that is configured to use Windows Integrated authentication (either connecting to Analysis Services or SQL Server back-end). Resources: Manage Kerberos Authentication Issues in a Reporting Services Environment http://download.microsoft.com/download/B/E/1/BE1AABB3-6ED8-4C3C-AF91-448AB733B1AF/SSRSKerberos.docx Configuring Kerberos Authentication for Microsoft SharePoint 2010 Products http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=23176 How to: Configure Windows Authentication in Reporting Services http://msdn.microsoft.com/en-us/library/cc281253.aspx RSReportServer Configuration File http://msdn.microsoft.com/en-us/library/ms157273.aspx#Authentication Planning for Browser Support http://msdn.microsoft.com/en-us/library/ms156511.aspx

  Read the article

• Finding the normal of OBB face with an OBB penetrating

  - by Milo

  Below is an illustration: I have an OBB in an OBB (see below for OBB2D code if needed). What I need to determine is, what face it is in, and what direction do I point the normal? The goal is to get the OBB out of the OBB so the normal needs to face outward of the OBB. How could I go about: Finding what face the line is penetrating given the 4 corners of the OBB and the class below: if we define dx=x2-x1 and dy=y2-y1, then the normals are (-dy, dx) and (dy, -dx). Which normal points outward of the OBB? Thanks public class OBB2D { // Corners of the box, where 0 is the lower left. private Vector2D corner[] = new Vector2D[4]; private Vector2D center = new Vector2D(); private Vector2D extents = new Vector2D(); private RectF boundingRect = new RectF(); private float angle; //Two edges of the box extended away from corner[0]. private Vector2D axis[] = new Vector2D[2]; private double origin[] = new double[2]; public OBB2D(Vector2D center, float w, float h, float angle) { set(center,w,h,angle); } public OBB2D(float left, float top, float width, float height) { set(new Vector2D(left + (width / 2), top + (height / 2)),width,height,0.0f); } public void set(Vector2D center,float w, float h,float angle) { Vector2D X = new Vector2D( (float)Math.cos(angle), (float)Math.sin(angle)); Vector2D Y = new Vector2D((float)-Math.sin(angle), (float)Math.cos(angle)); X = X.multiply( w / 2); Y = Y.multiply( h / 2); corner[0] = center.subtract(X).subtract(Y); corner[1] = center.add(X).subtract(Y); corner[2] = center.add(X).add(Y); corner[3] = center.subtract(X).add(Y); computeAxes(); extents.x = w / 2; extents.y = h / 2; computeDimensions(center,angle); } private void computeDimensions(Vector2D center,float angle) { this.center.x = center.x; this.center.y = center.y; this.angle = angle; boundingRect.left = Math.min(Math.min(corner[0].x, corner[3].x), Math.min(corner[1].x, corner[2].x)); boundingRect.top = Math.min(Math.min(corner[0].y, corner[1].y),Math.min(corner[2].y, corner[3].y)); boundingRect.right = Math.max(Math.max(corner[1].x, corner[2].x), Math.max(corner[0].x, corner[3].x)); boundingRect.bottom = Math.max(Math.max(corner[2].y, corner[3].y),Math.max(corner[0].y, corner[1].y)); } public void set(RectF rect) { set(new Vector2D(rect.centerX(),rect.centerY()),rect.width(),rect.height(),0.0f); } // Returns true if other overlaps one dimension of this. private boolean overlaps1Way(OBB2D other) { for (int a = 0; a < axis.length; ++a) { double t = other.corner[0].dot(axis[a]); // Find the extent of box 2 on axis a double tMin = t; double tMax = t; for (int c = 1; c < corner.length; ++c) { t = other.corner[c].dot(axis[a]); if (t < tMin) { tMin = t; } else if (t > tMax) { tMax = t; } } // We have to subtract off the origin // See if [tMin, tMax] intersects [0, 1] if ((tMin > 1 + origin[a]) || (tMax < origin[a])) { // There was no intersection along this dimension; // the boxes cannot possibly overlap. return false; } } // There was no dimension along which there is no intersection. // Therefore the boxes overlap. return true; } //Updates the axes after the corners move. Assumes the //corners actually form a rectangle. private void computeAxes() { axis[0] = corner[1].subtract(corner[0]); axis[1] = corner[3].subtract(corner[0]); // Make the length of each axis 1/edge length so we know any // dot product must be less than 1 to fall within the edge. for (int a = 0; a < axis.length; ++a) { axis[a] = axis[a].divide((axis[a].length() * axis[a].length())); origin[a] = corner[0].dot(axis[a]); } } public void moveTo(Vector2D center) { Vector2D centroid = (corner[0].add(corner[1]).add(corner[2]).add(corner[3])).divide(4.0f); Vector2D translation = center.subtract(centroid); for (int c = 0; c < 4; ++c) { corner[c] = corner[c].add(translation); } computeAxes(); computeDimensions(center,angle); } // Returns true if the intersection of the boxes is non-empty. public boolean overlaps(OBB2D other) { if(right() < other.left()) { return false; } if(bottom() < other.top()) { return false; } if(left() > other.right()) { return false; } if(top() > other.bottom()) { return false; } if(other.getAngle() == 0.0f && getAngle() == 0.0f) { return true; } return overlaps1Way(other) && other.overlaps1Way(this); } public Vector2D getCenter() { return center; } public float getWidth() { return extents.x * 2; } public float getHeight() { return extents.y * 2; } public void setAngle(float angle) { set(center,getWidth(),getHeight(),angle); } public float getAngle() { return angle; } public void setSize(float w,float h) { set(center,w,h,angle); } public float left() { return boundingRect.left; } public float right() { return boundingRect.right; } public float bottom() { return boundingRect.bottom; } public float top() { return boundingRect.top; } public RectF getBoundingRect() { return boundingRect; } public boolean overlaps(float left, float top, float right, float bottom) { if(right() < left) { return false; } if(bottom() < top) { return false; } if(left() > right) { return false; } if(top() > bottom) { return false; } return true; } };

  Read the article

• Move penetrating OBB out of another OBB to resolve collision

  - by Milo

  I'm working on collision resolution for my game. I just need a good way to get an object out of another object if it gets stuck. In this case a car. Here is a typical scenario. The red car is in the green object. How do I correctly get it out so the car can slide along the edge of the object as it should. I tried: if(buildings.size() > 0) { Entity e = buildings.get(0); Vector2D vel = new Vector2D(); vel.x = vehicle.getVelocity().x; vel.y = vehicle.getVelocity().y; vel.normalize(); while(vehicle.getRect().overlaps(e.getRect())) { vehicle.setCenter(vehicle.getCenterX() - vel.x * 0.1f, vehicle.getCenterY() - vel.y * 0.1f); } colided = true; } But that does not work too well. Is there some sort of vector I could calculate to use as the vector to move the car away from the object? Thanks Here is my OBB2D class: public class OBB2D { // Corners of the box, where 0 is the lower left. private Vector2D corner[] = new Vector2D[4]; private Vector2D center = new Vector2D(); private Vector2D extents = new Vector2D(); private RectF boundingRect = new RectF(); private float angle; //Two edges of the box extended away from corner[0]. private Vector2D axis[] = new Vector2D[2]; private double origin[] = new double[2]; public OBB2D(Vector2D center, float w, float h, float angle) { set(center,w,h,angle); } public OBB2D(float left, float top, float width, float height) { set(new Vector2D(left + (width / 2), top + (height / 2)),width,height,0.0f); } public void set(Vector2D center,float w, float h,float angle) { Vector2D X = new Vector2D( (float)Math.cos(angle), (float)Math.sin(angle)); Vector2D Y = new Vector2D((float)-Math.sin(angle), (float)Math.cos(angle)); X = X.multiply( w / 2); Y = Y.multiply( h / 2); corner[0] = center.subtract(X).subtract(Y); corner[1] = center.add(X).subtract(Y); corner[2] = center.add(X).add(Y); corner[3] = center.subtract(X).add(Y); computeAxes(); extents.x = w / 2; extents.y = h / 2; computeDimensions(center,angle); } private void computeDimensions(Vector2D center,float angle) { this.center.x = center.x; this.center.y = center.y; this.angle = angle; boundingRect.left = Math.min(Math.min(corner[0].x, corner[3].x), Math.min(corner[1].x, corner[2].x)); boundingRect.top = Math.min(Math.min(corner[0].y, corner[1].y),Math.min(corner[2].y, corner[3].y)); boundingRect.right = Math.max(Math.max(corner[1].x, corner[2].x), Math.max(corner[0].x, corner[3].x)); boundingRect.bottom = Math.max(Math.max(corner[2].y, corner[3].y),Math.max(corner[0].y, corner[1].y)); } public void set(RectF rect) { set(new Vector2D(rect.centerX(),rect.centerY()),rect.width(),rect.height(),0.0f); } // Returns true if other overlaps one dimension of this. private boolean overlaps1Way(OBB2D other) { for (int a = 0; a < axis.length; ++a) { double t = other.corner[0].dot(axis[a]); // Find the extent of box 2 on axis a double tMin = t; double tMax = t; for (int c = 1; c < corner.length; ++c) { t = other.corner[c].dot(axis[a]); if (t < tMin) { tMin = t; } else if (t > tMax) { tMax = t; } } // We have to subtract off the origin // See if [tMin, tMax] intersects [0, 1] if ((tMin > 1 + origin[a]) || (tMax < origin[a])) { // There was no intersection along this dimension; // the boxes cannot possibly overlap. return false; } } // There was no dimension along which there is no intersection. // Therefore the boxes overlap. return true; } //Updates the axes after the corners move. Assumes the //corners actually form a rectangle. private void computeAxes() { axis[0] = corner[1].subtract(corner[0]); axis[1] = corner[3].subtract(corner[0]); // Make the length of each axis 1/edge length so we know any // dot product must be less than 1 to fall within the edge. for (int a = 0; a < axis.length; ++a) { axis[a] = axis[a].divide((axis[a].length() * axis[a].length())); origin[a] = corner[0].dot(axis[a]); } } public void moveTo(Vector2D center) { Vector2D centroid = (corner[0].add(corner[1]).add(corner[2]).add(corner[3])).divide(4.0f); Vector2D translation = center.subtract(centroid); for (int c = 0; c < 4; ++c) { corner[c] = corner[c].add(translation); } computeAxes(); computeDimensions(center,angle); } // Returns true if the intersection of the boxes is non-empty. public boolean overlaps(OBB2D other) { if(right() < other.left()) { return false; } if(bottom() < other.top()) { return false; } if(left() > other.right()) { return false; } if(top() > other.bottom()) { return false; } if(other.getAngle() == 0.0f && getAngle() == 0.0f) { return true; } return overlaps1Way(other) && other.overlaps1Way(this); } public Vector2D getCenter() { return center; } public float getWidth() { return extents.x * 2; } public float getHeight() { return extents.y * 2; } public void setAngle(float angle) { set(center,getWidth(),getHeight(),angle); } public float getAngle() { return angle; } public void setSize(float w,float h) { set(center,w,h,angle); } public float left() { return boundingRect.left; } public float right() { return boundingRect.right; } public float bottom() { return boundingRect.bottom; } public float top() { return boundingRect.top; } public RectF getBoundingRect() { return boundingRect; } public boolean overlaps(float left, float top, float right, float bottom) { if(right() < left) { return false; } if(bottom() < top) { return false; } if(left() > right) { return false; } if(top() > bottom) { return false; } return true; } };

  Read the article

• readonly keyword

  - by nmarun

  This is something new that I learned about the readonly keyword. Have a look at the following class: 1: public class MyClass 2: { 3: public string Name { get; set; } 4: public int Age { get; set; } 5:  6: private readonly double Delta; 7:  8: public MyClass() 9: { 10: Initializer(); 11: } 12:  13: public MyClass(string name = "", int age = 0) 14: { 15: Name = name; 16: Age = age; 17: Initializer(); 18: } 19:  20: private void Initializer() 21: { 22: Delta = 0.2; 23: } 24: } I have a couple of public properties and a private readonly member. There are two constructors – one that doesn’t take any parameters and the other takes two parameters to initialize the public properties. I’m also calling the Initializer method in both constructors to initialize the readonly member. Now when I build this, the code breaks and the Error window says: “A readonly field cannot be assigned to (except in a constructor or a variable initializer)” Two things after I read this message: It’s such a negative statement. I’d prefer something like: “A readonly field can be assigned to (or initialized) only in a constructor or through a variable initializer” But in my defense, I AM assigning it in a constructor (only indirectly). All I’m doing is creating a method that does it and calling it in a constructor. Turns out, .net was not ‘frameworked’ this way. We need to have the member initialized directly in the constructor. If you have multiple constructors, you can just use the ‘this’ keyword on all except the default constructors to call the default constructor. This default constructor can then initialize your readonly members. This will ensure you’re not repeating the code in multiple places. A snippet of what I’m talking can be seen below: 1: public class Person 2: { 3: public int UniqueNumber { get; set; } 4: public string Name { get; set; } 5: public int Age { get; set; } 6: public DateTime DateOfBirth { get; set; } 7: public string InvoiceNumber { get; set; } 8:  9: private readonly string Alpha; 10: private readonly int Beta; 11: private readonly double Delta; 12: private readonly double Gamma; 13:  14: public Person() 15: { 16: Alpha = "FDSA"; 17: Beta = 2; 18: Delta = 3.0; 19: Gamma = 0.0989; 20: } 21:  22: public Person(int uniqueNumber) : this() 23: { 24: UniqueNumber = uniqueNumber; 25: } 26: } See the syntax in line 22 and you’ll know what I’m talking about. So the default constructor gets called before the one in line 22. These are known as constructor initializers and they allow one constructor to call another. The other ‘myth’ I had about readonly members is that you can set it’s value only once. This was busted as well (I recall Adam and Jamie’s show). Say you’ve initialized the readonly member through a variable initializer. You can over-write this value in any of the constructors any number of times. 1: public class Person 2: { 3: public int UniqueNumber { get; set; } 4: public string Name { get; set; } 5: public int Age { get; set; } 6: public DateTime DateOfBirth { get; set; } 7: public string InvoiceNumber { get; set; } 8:  9: private readonly string Alpha = "asdf"; 10: private readonly int Beta = 15; 11: private readonly double Delta = 0.077; 12: private readonly double Gamma = 1.0; 13:  14: public Person() 15: { 16: Alpha = "FDSA"; 17: Beta = 2; 18: Delta = 3.0; 19: Gamma = 0.0989; 20: } 21:  22: public Person(int uniqueNumber) : this() 23: { 24: UniqueNumber = uniqueNumber; 25: Beta = 3; 26: } 27:  28: public Person(string name, DateTime dob) : this() 29: { 30: Name = name; 31: DateOfBirth = dob; 32:  33: Alpha = ";LKJ"; 34: Gamma = 0.0898; 35: } 36:  37: public Person(int uniqueNumber, string name, int age, DateTime dob, string invoiceNumber) : this() 38: { 39: UniqueNumber = uniqueNumber; 40: Name = name; 41: Age = age; 42: DateOfBirth = dob; 43: InvoiceNumber = invoiceNumber; 44:  45: Alpha = "QWER"; 46: Beta = 5; 47: Delta = 1.0; 48: Gamma = 0.0; 49: } 50: } In the above example, every constructor over-writes the values for the readonly members. This is perfectly valid. There is a possibility that based on the way the object is instantiated, the readonly member will have a different value. Well, that’s all I have for today and read this as it’s on a related topic.

  Read the article

• The code works but when using printf it gives me a weird answer. Help please [closed]

  - by user71458

  //Programmer-William Chen //Seventh Period Computer Science II //Problem Statement - First get the elapsed times and the program will find the //split times for the user to see. // //Algorithm- First the programmer makes the prototype and calls them in the //main function. The programmer then asks the user to input lap time data. //Secondly, you convert the splits into seconds and subtract them so you can //find the splits. Then the average is all the lap time's in seconds. Finally, //the programmer printf all the results for the user to see. #include <iostream> #include <stdlib.h> #include <math.h> #include <conio.h> #include <stdio.h> using namespace std; void thisgetsElapsedTimes( int &m1, int &m2, int &m3, int &m4, int &m5, int &s1, int &s2, int &s3, int &s4, int &s5); //this is prototype void thisconvertstoseconds ( int &m1, int &m2, int &m3, int &m4, int &m5, int &s1, int &s2, int &s3, int &s4, int &s5, int &split1, int &split2, int &split3, int &split4, int &split5);//this too void thisfindsSplits(int &m1, int &m2, int &m3, int &m4, int &m5, int &split1, int &split2, int &split3, int &split4, int &split5, int &split6, int &split7, int &split8, int &split9, int &split10);// this is part of prototype void thisisthesecondconversation (int &split1M, int &split2M, int &split3M, int &split4M, int &split5M, int &split1S,int &split2S, int &split3S, int &split4S, int &split5S, int &split1, int &split2, int &split3, int &split4, int &split5);//this gets a value void thisfindstheaverage(double &average, int &split1, int &split2, int &split3, int &split4, int &split5);//and this void thisprintsstuff( int &split1M, int &split2M, int &split3M, int &split4M, int &split5M, int &split1S, int &split2S, int &split3S, int &split4S, int &split5S, double &average); //this prints int main(int argc, char *argv[]) { int m1, m2, m3, m4, m5, s1, s2, s3, s4, s5, split1, split2, split3, split4, split5, split1M, split2M, split3M, split4M, split5M, split1S, split2S, split3S, split4S, split5S; int split6, split7, split8, split9, split10; double average; char thistakescolon; thisgetsElapsedTimes ( m1, m2, m3, m4, m5, s1, s2, s3, s4, s5); thisconvertstoseconds ( m1, m2, m3, m4, m5, s1, s2, s3, s4, s5, split1, split2, split3, split4, split5); thisfindsSplits ( m1, m2, m3, m4, m5, split1, split2, split3, split4, split5, split6, split7, split8, split9, split10); thisisthesecondconversation ( split1M, split2M, split3M, split4M, split5M, split1S, split2S, split3S, split4S, split5S, split1, split2, split3, split4, split5); thisfindstheaverage ( average, split1, split2, split3, split4, split5); thisprintsstuff ( split1M, split2M, split3M, split4M, split5M, split1S, split2S, split3S, split4S, split5S, average); // these are calling statements and they call from the main function to the other functions. system("PAUSE"); return 0; } void thisgetsElapsedTimes(int &m1, int &m2, int &m3, int &m4, int &m5, int &s1, int &s2, int &s3, int &s4, int &s5) { char thistakescolon; cout << "Enter the elapsed time:" << endl; cout << " Kilometer 1 "; cin m1 thistakescolon s1; cout << " Kilometer 2 "; cin m2 thistakescolon s2; cout << " Kilometer 3 " ; cin m3 thistakescolon s3; cout << " Kilometer 4 "; cin m4 thistakescolon s4; cout << " Kilometer 5 "; cin m5 thistakescolon s5; // this gets the data required to get the results needed for the user to see // . } void thisconvertstoseconds (int &m1, int &m2, int &m3, int &m4, int &m5, int &s1, int &s2, int &s3, int &s4, int &s5, int &split1, int &split2, int &split3, int &split4, int &split5) { split1 = (m1 * 60) + s1;//this converts for minutes to seconds for m1 split2 = (m2 * 60) + s2;//this converts for minutes to seconds for m2 split3 = (m3 * 60) + s3;//this converts for minutes to seconds for m3 split4 = (m4 * 60) + s4;//this converts for minutes to seconds for m4 split5 = (m5 * 60) + s5;//this converts for minutes to seconds for m5 } void thisfindsSplits (int &m1, int &m2, int &m3, int &m4, int &m5,int &split1, int &split2, int &split3, int &split4, int &split5, int &split6, int &split7, int &split8, int &split9, int &split10)//this is function heading { split6 = split1; //this is split for the first lap. split7 = split2 - split1;//this is split for the second lap. split8 = split3 - split2;//this is split for the third lap. split9 = split4 - split3;//this is split for the fourth lap. split10 = split5 - split4;//this is split for the fifth lap. } void thisfindstheaverage(double &average, int &split1, int &split2, int &split3, int &split4, int &split5) { average = (split1 + split2 + split3 + split4 + split5)/5; // this finds the average from all the splits in seconds } void thisisthesecondconversation (int &split1M, int &split2M, int &split3M, int &split4M, int &split5M, int &split1S,int &split2S, int &split3S, int &split4S, int &split5S, int &split1, int &split2, int &split3, int &split4, int &split5) { split1M = split1 * 60; //this finds the split times split1S = split1M - split1 * 60; //then this finds split2M = split2 * 60; //and all of this split2S = split2M - split2 * 60; //does basically split3M = split3 * 60; //the same thing split3S = split3M - split3 * 60; //all of it split4M = split4 * 60; //it's also a split4S = split4M - split4 * 60; //function split5M = split5 * 60; //and it finds the splits split5S = split5M - split5 * 60; //for each lap. } void thisprintsstuff (int &split1M, int &split2M, int &split3M, int &split4M, int &split5M, int &split1S, int &split2S, int &split3S, int &split4S, int &split5S, double &average)// this is function heading { printf("\n kilometer 1 %d" , ":02%d",'split1M','split1S'); printf("\n kilometer 2 %d" , ":02%d",'split2M','split2S'); printf("\n kilometer 3 %d" , ":02%d",'split3M','split3S'); printf("\n kilometer 4 %d" , ":02%d",'split4M','split4S'); printf("\n kilometer 5 %d" , ":02%d",'split5M','split5S'); printf("\n your average pace is ",'average',"per kilometer \n", "William Chen\n"); // this printf so the programmer // can allow the user to see // the results from the data gathered. }

  Read the article

• Problem Implementing Texture on Libgdx Mesh of Randomized Terrain

  - by BrotherJack

  I'm having problems understanding how to apply a texture to a non-rectangular object. The following code creates textures such as this: from the debug renderer I think I've got the physical shape of the "earth" correct. However, I don't know how to apply a texture to it. I have a 50x50 pixel image (in the environment constructor as "dirt.png"), that I want to apply to the hills. I have a vague idea that this seems to involve the mesh class and possibly a ShapeRenderer, but the little i'm finding online is just confusing me. Bellow is code from the class that makes and regulates the terrain and the code in a separate file that is supposed to render it (but crashes on the mesh.render() call). Any pointers would be appreciated. public class Environment extends Actor{ Pixmap sky; public Texture groundTexture; Texture skyTexture; double tankypos; //TODO delete, temp public Tank etank; //TODO delete, temp int destructionRes; // how wide is a static pixel private final float viewWidth; private final float viewHeight; private ChainShape terrain; public Texture dirtTexture; private World world; public Mesh terrainMesh; private static final String LOG = Environment.class.getSimpleName(); // Constructor public Environment(Tank tank, FileHandle sfileHandle, float w, float h, int destructionRes) { world = new World(new Vector2(0, -10), true); this.destructionRes = destructionRes; sky = new Pixmap(sfileHandle); viewWidth = w; viewHeight = h; skyTexture = new Texture(sky); terrain = new ChainShape(); genTerrain((int)w, (int)h, 6); Texture tankSprite = new Texture(Gdx.files.internal("TankSpriteBase.png")); Texture turretSprite = new Texture(Gdx.files.internal("TankSpriteTurret.png")); tank = new Tank(0, true, tankSprite, turretSprite); Rectangle tankrect = new Rectangle(300, (int)tankypos, 44, 45); tank.setRect(tankrect); BodyDef terrainDef = new BodyDef(); terrainDef.type = BodyType.StaticBody; terrainDef.position.set(0, 0); Body terrainBody = world.createBody(terrainDef); FixtureDef fixtureDef = new FixtureDef(); fixtureDef.shape = terrain; terrainBody.createFixture(fixtureDef); BodyDef tankDef = new BodyDef(); Rectangle rect = tank.getRect(); tankDef.type = BodyType.DynamicBody; tankDef.position.set(0,0); tankDef.position.x = rect.x; tankDef.position.y = rect.y; Body tankBody = world.createBody(tankDef); FixtureDef tankFixture = new FixtureDef(); PolygonShape shape = new PolygonShape(); shape.setAsBox(rect.width*WORLD_TO_BOX, rect.height*WORLD_TO_BOX); fixtureDef.shape = shape; dirtTexture = new Texture(Gdx.files.internal("dirt.png")); etank = tank; } private void genTerrain(int w, int h, int hillnessFactor){ int width = w; int height = h; Random rand = new Random(); //min and max bracket the freq's of the sin/cos series //The higher the max the hillier the environment int min = 1; //allocating horizon for screen width Vector2[] horizon = new Vector2[width+2]; horizon[0] = new Vector2(0,0); double[] skyline = new double[width]; //TODO skyline necessary as an array? //ratio of amplitude of screen height to landscape variation double r = (int) 2.0/5.0; //number of terms to be used in sine/cosine series int n = 4; int[] f = new int[n*2]; //calculating omegas for sine series for(int i = 0; i < n*2 ; i ++){ f[i] = rand.nextInt(hillnessFactor - min + 1) + min; } //amp is the amplitude of the series int amp = (int) (r*height); double lastPoint = 0.0; for(int i = 0 ; i < width; i ++){ skyline[i] = 0; for(int j = 0; j < n; j++){ skyline[i] += ( Math.sin( (f[j]*Math.PI*i/height) ) + Math.cos(f[j+n]*Math.PI*i/height) ); } skyline[i] *= amp/(n*2); skyline[i] += (height/2); skyline[i] = (int)skyline[i]; //TODO Possible un-necessary float to int to float conversions tankypos = skyline[i]; horizon[i+1] = new Vector2((float)i, (float)skyline[i]); if(i == width) lastPoint = skyline[i]; } horizon[width+1] = new Vector2(800, (float)lastPoint); terrain.createChain(horizon); terrain.createLoop(horizon); //I have no idea if the following does anything useful :( terrainMesh = new Mesh(true, (width+2)*2, (width+2)*2, new VertexAttribute(Usage.Position, (width+2)*2, "a_position")); float[] vertices = new float[(width+2)*2]; short[] indices = new short[(width+2)*2]; for(int i=0; i < (width+2); i+=2){ vertices[i] = horizon[i].x; vertices[i+1] = horizon[i].y; indices[i] = (short)i; indices[i+1] = (short)(i+1); } terrainMesh.setVertices(vertices); terrainMesh.setIndices(indices); } Here is the code that is (supposed to) render the terrain. @Override public void render(float delta) { Gdx.gl.glClearColor(1, 1, 1, 1); Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); // tell the camera to update its matrices. camera.update(); // tell the SpriteBatch to render in the // coordinate system specified by the camera. backgroundStage.draw(); backgroundStage.act(delta); uistage.draw(); uistage.act(delta); batch.begin(); debugRenderer.render(this.ground.getWorld(), camera.combined); batch.end(); //Gdx.graphics.getGL10().glEnable(GL10.GL_TEXTURE_2D); ground.dirtTexture.bind(); ground.terrainMesh.render(GL10.GL_TRIANGLE_FAN); //I'm particularly lost on this ground.step(); }

  Read the article

• Issues with signal handling [closed]

  - by user34790

  I am trying to actually study the signal handling behavior in multiprocess system. I have a system where there are three signal generating processes generating signals of type SIGUSR1 and SIGUSR1. I have two handler processes that handle a particular type of signal. I have another monitoring process that also receives the signals and then does its work. I have a certain issue. Whenever my signal handling processes generate a signal of a particular type, it is sent to the process group so it is received by the signal handling processes as well as the monitoring processes. Whenever the signal handlers of monitoring and signal handling processes are called, I have printed to indicate the signal handling. I was expecting a uniform series of calls for the signal handlers of the monitoring and handling processes. However, looking at the output I could see like at the beginning the monitoring and signal handling processes's signal handlers are called uniformly. However, after I could see like signal handler processes handlers being called in a burst followed by the signal handler of monitoring process being called in a burst. Here is my code and output #include <iostream> #include <sys/types.h> #include <sys/wait.h> #include <sys/time.h> #include <signal.h> #include <cstdio> #include <stdlib.h> #include <sys/ipc.h> #include <sys/shm.h> #define NUM_SENDER_PROCESSES 3 #define NUM_HANDLER_PROCESSES 4 #define NUM_SIGNAL_REPORT 10 #define MAX_SIGNAL_COUNT 100000 using namespace std; volatile int *usrsig1_handler_count; volatile int *usrsig2_handler_count; volatile int *usrsig1_sender_count; volatile int *usrsig2_sender_count; volatile int *lock_1; volatile int *lock_2; volatile int *lock_3; volatile int *lock_4; volatile int *lock_5; volatile int *lock_6; //Used only by the monitoring process volatile int monitor_count; volatile int usrsig1_monitor_count; volatile int usrsig2_monitor_count; double time_1[NUM_SIGNAL_REPORT]; double time_2[NUM_SIGNAL_REPORT]; //Used only by the main process int total_signal_count; //For shared memory int shmid; const int shareSize = sizeof(int) * (10); double timestamp() { struct timeval tp; gettimeofday(&tp, NULL); return (double)tp.tv_sec + tp.tv_usec / 1000000.; } pid_t senders[NUM_SENDER_PROCESSES]; pid_t handlers[NUM_HANDLER_PROCESSES]; pid_t reporter; void signal_catcher_1(int); void signal_catcher_2(int); void signal_catcher_int(int); void signal_catcher_monitor(int); void signal_catcher_main(int); void terminate_processes() { //Kill the child processes int status; cout << "Time up terminating the child processes" << endl; for(int i=0; i<NUM_SENDER_PROCESSES; i++) { kill(senders[i],SIGKILL); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { kill(handlers[i],SIGKILL); } kill(reporter,SIGKILL); //Wait for the child processes to finish for(int i=0; i<NUM_SENDER_PROCESSES; i++) { waitpid(senders[i], &status, 0); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { waitpid(handlers[i], &status, 0); } waitpid(reporter, &status, 0); } int main(int argc, char *argv[]) { if(argc != 2) { cout << "Required parameters missing. " << endl; cout << "Option 1 = 1 which means run for 30 seconds" << endl; cout << "Option 2 = 2 which means run until 100000 signals" << endl; exit(0); } int option = atoi(argv[1]); pid_t pid; if(option == 2) { if(signal(SIGUSR1, signal_catcher_main) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, signal_catcher_main) == SIG_ERR) { perror("2"); exit(1); } } else { if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } } if(signal(SIGINT, signal_catcher_int) == SIG_ERR) { perror("3"); exit(1); } /////////////////////////////////////////////////////////////////////////////////////// ////////////////////// Initializing the shared memory ///////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////// cout << "Initializing the shared memory" << endl; if ((shmid=shmget(IPC_PRIVATE,shareSize,IPC_CREAT|0660))< 0) { perror("shmget fail"); exit(1); } usrsig1_handler_count = (int *) shmat(shmid, NULL, 0); usrsig2_handler_count = usrsig1_handler_count + 1; usrsig1_sender_count = usrsig2_handler_count + 1; usrsig2_sender_count = usrsig1_sender_count + 1; lock_1 = usrsig2_sender_count + 1; lock_2 = lock_1 + 1; lock_3 = lock_2 + 1; lock_4 = lock_3 + 1; lock_5 = lock_4 + 1; lock_6 = lock_5 + 1; //Initialize them to be zero *usrsig1_handler_count = 0; *usrsig2_handler_count = 0; *usrsig1_sender_count = 0; *usrsig2_sender_count = 0; *lock_1 = 0; *lock_2 = 0; *lock_3 = 0; *lock_4 = 0; *lock_5 = 0; *lock_6 = 0; cout << "End of initializing the shared memory" << endl; ///////////////////////////////////////////////////////////////////////////////////////////// /////////////////// End of initializing the shared memory /////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// /////////////////////////////Registering the signal handlers/////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the signal handlers" << endl; for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { if((pid = fork()) == 0) { if(i%2 == 0) { struct sigaction action; action.sa_handler = signal_catcher_1; sigset_t block_mask; action.sa_flags = 0; sigaction(SIGUSR1,&action,NULL); if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } } else { if(signal(SIGUSR1 ,SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } struct sigaction action; action.sa_handler = signal_catcher_2; action.sa_flags = 0; sigaction(SIGUSR2,&action,NULL); } if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } while(true) { pause(); } exit(0); } else { //cout << "Registerd the handler " << pid << endl; handlers[i] = pid; } } cout << "End of registering the signal handlers" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////////End of registering the signal handlers ////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////////////////// ///////////////////////////Registering the monitoring process ////////////////////////////////////// //////////////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the monitoring process" << endl; if((pid = fork()) == 0) { struct sigaction action; action.sa_handler = signal_catcher_monitor; sigemptyset(&action.sa_mask); sigset_t block_mask; sigemptyset(&block_mask); sigaddset(&block_mask,SIGUSR1); sigaddset(&block_mask,SIGUSR2); action.sa_flags = 0; action.sa_mask = block_mask; sigaction(SIGUSR1,&action,NULL); sigaction(SIGUSR2,&action,NULL); if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } while(true) { pause(); } exit(0); } else { cout << "Monitor's pid is " << pid << endl; reporter = pid; } cout << "End of registering the monitoring process" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// ////////////////////////End of registering the monitoring process//////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //Sleep to make sure that the monitor and handler processes are well initialized and ready to handle signals sleep(5); ////////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////Registering the signal generators/////////////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// cout << "Registering the signal generators" << endl; for(int i=0; i<NUM_SENDER_PROCESSES; i++) { if((pid = fork()) == 0) { if(signal(SIGUSR1, SIG_IGN) == SIG_ERR) { perror("1"); exit(1); } if(signal(SIGUSR2, SIG_IGN) == SIG_ERR) { perror("2"); exit(1); } if(signal(SIGINT, SIG_DFL) == SIG_ERR) { perror("2"); exit(1); } srand(i); while(true) { int signal_id = rand()%2 + 1; if(signal_id == 1) { killpg(getpgid(getpid()), SIGUSR1); while(__sync_lock_test_and_set(lock_4,1) != 0) { } (*usrsig1_sender_count)++; *lock_4 = 0; } else { killpg(getpgid(getpid()), SIGUSR2); while(__sync_lock_test_and_set(lock_5,1) != 0) { } (*usrsig2_sender_count)++; *lock_5=0; } int r = rand()%10 + 1; double s = (double)r/100; sleep(s); } exit(0); } else { //cout << "Registered the sender " << pid << endl; senders[i] = pid; } } //cout << "End of registering the signal generators" << endl; ///////////////////////////////////////////////////////////////////////////////////////////////////// //////////////////////////End of registering the signal generators/////////////////////////////////// ///////////////////////////////////////////////////////////////////////////////////////////////////// //Either sleep for 30 seconds and terminate the program or if the number of signals generated reaches 10000, terminate the program if(option = 1) { sleep(90); terminate_processes(); } else { while(true) { if(total_signal_count >= MAX_SIGNAL_COUNT) { terminate_processes(); } else { sleep(0.001); } } } } void signal_catcher_1(int the_sig) { while(__sync_lock_test_and_set(lock_1,1) != 0) { } (*usrsig1_handler_count) = (*usrsig1_handler_count) + 1; cout << "Signal Handler 1 " << *usrsig1_handler_count << endl; __sync_lock_release(lock_1); } void signal_catcher_2(int the_sig) { while(__sync_lock_test_and_set(lock_2,1) != 0) { } (*usrsig2_handler_count) = (*usrsig2_handler_count) + 1; __sync_lock_release(lock_2); } void signal_catcher_main(int the_sig) { while(__sync_lock_test_and_set(lock_6,1) != 0) { } total_signal_count++; *lock_6 = 0; } void signal_catcher_int(int the_sig) { for(int i=0; i<NUM_SENDER_PROCESSES; i++) { kill(senders[i],SIGKILL); } for(int i=0; i<NUM_HANDLER_PROCESSES; i++) { kill(handlers[i],SIGKILL); } kill(reporter,SIGKILL); exit(3); } void signal_catcher_monitor(int the_sig) { cout << "Monitoring process " << *usrsig1_handler_count << endl; } Here is the initial segment of output Monitoring process 0 Monitoring process 0 Monitoring process 0 Monitoring process 0 Signal Handler 1 1 Monitoring process 2 Signal Handler 1 2 Signal Handler 1 3 Signal Handler 1 4 Monitoring process 4 Monitoring process Signal Handler 1 6 Signal Handler 1 7 Monitoring process 7 Monitoring process 8 Monitoring process 8 Signal Handler 1 9 Monitoring process 9 Monitoring process 9 Monitoring process 10 Signal Handler 1 11 Monitoring process 11 Monitoring process 12 Signal Handler 1 13 Signal Handler 1 14 Signal Handler 1 15 Signal Handler 1 16 Signal Handler 1 17 Signal Handler 1 18 Monitoring process 19 Signal Handler 1 20 Monitoring process 20 Signal Handler 1 21 Monitoring process 21 Monitoring process 21 Monitoring process 22 Monitoring process 22 Monitoring process 23 Signal Handler 1 24 Signal Handler 1 25 Monitoring process 25 Signal Handler 1 27 Signal Handler 1 28 Signal Handler 1 29 Here is the segment when the signal handler processes signal handlers are called in a burst Signal Handler 1 456 Signal Handler 1 457 Signal Handler 1 458 Signal Handler 1 459 Signal Handler 1 460 Signal Handler 1 461 Signal Handler 1 462 Signal Handler 1 463 Signal Handler 1 464 Signal Handler 1 465 Signal Handler 1 466 Signal Handler 1 467 Signal Handler 1 468 Signal Handler 1 469 Signal Handler 1 470 Signal Handler 1 471 Signal Handler 1 472 Signal Handler 1 473 Signal Handler 1 474 Signal Handler 1 475 Signal Handler 1 476 Signal Handler 1 477 Signal Handler 1 478 Signal Handler 1 479 Signal Handler 1 480 Signal Handler 1 481 Signal Handler 1 482 Signal Handler 1 483 Signal Handler 1 484 Signal Handler 1 485 Signal Handler 1 486 Signal Handler 1 487 Signal Handler 1 488 Signal Handler 1 489 Signal Handler 1 490 Signal Handler 1 491 Signal Handler 1 492 Signal Handler 1 493 Signal Handler 1 494 Signal Handler 1 495 Signal Handler 1 496 Signal Handler 1 497 Signal Handler 1 498 Signal Handler 1 499 Signal Handler 1 500 Signal Handler 1 501 Signal Handler 1 502 Signal Handler 1 503 Signal Handler 1 504 Signal Handler 1 505 Signal Handler 1 506 Here is the segment when the monitoring processes signal handlers are called in a burst Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Monitoring process 140 Why isn't it uniform afterwards. Why are they called in a burst?

  Read the article

• C#/.NET Little Wonders: Interlocked CompareExchange()

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Two posts ago, I discussed the Interlocked Add(), Increment(), and Decrement() methods (here) for adding and subtracting values in a thread-safe, lightweight manner.  Then, last post I talked about the Interlocked Read() and Exchange() methods (here) for safely and efficiently reading and setting 32 or 64 bit values (or references).  This week, we’ll round out the discussion by talking about the Interlocked CompareExchange() method and how it can be put to use to exchange a value if the current value is what you expected it to be. Dirty reads can lead to bad results Many of the uses of Interlocked that we’ve explored so far have centered around either reading, setting, or adding values.  But what happens if you want to do something more complex such as setting a value based on the previous value in some manner? Perhaps you were creating an application that reads a current balance, applies a deposit, and then saves the new modified balance, where of course you’d want that to happen atomically.  If you read the balance, then go to save the new balance and between that time the previous balance has already changed, you’ll have an issue!  Think about it, if we read the current balance as $400, and we are applying a new deposit of $50.75, but meanwhile someone else deposits $200 and sets the total to $600, but then we write a total of $450.75 we’ve lost $200! Now, certainly for int and long values we can use Interlocked.Add() to handles these cases, and it works well for that.  But what if we want to work with doubles, for example?  Let’s say we wanted to add the numbers from 0 to 99,999 in parallel.  We could do this by spawning several parallel tasks to continuously add to a total: 1: double total = 0; 2:  3: Parallel.For(0, 10000, next => 4: { 5: total += next; 6: }); Were this run on one thread using a standard for loop, we’d expect an answer of 4,999,950,000 (the sum of all numbers from 0 to 99,999).  But when we run this in parallel as written above, we’ll likely get something far off.  The result of one of my runs, for example, was 1,281,880,740.  That is way off!  If this were banking software we’d be in big trouble with our clients.  So what happened?  The += operator is not atomic, it will read in the current value, add the result, then store it back into the total.  At any point in all of this another thread could read a “dirty” current total and accidentally “skip” our add.   So, to clean this up, we could use a lock to guarantee concurrency: 1: double total = 0.0; 2: object locker = new object(); 3:  4: Parallel.For(0, count, next => 5: { 6: lock (locker) 7: { 8: total += next; 9: } 10: }); Which will give us the correct result of 4,999,950,000.  One thing to note is that locking can be heavy, especially if the operation being locked over is trivial, or the life of the lock is a high percentage of the work being performed concurrently.  In the case above, the lock consumes pretty much all of the time of each parallel task – and the task being locked on is relatively trivial. Now, let me put in a disclaimer here before we go further: For most uses, lock is more than sufficient for your needs, and is often the simplest solution!    So, if lock is sufficient for most needs, why would we ever consider another solution?  The problem with locking is that it can suspend execution of your thread while it waits for the signal that the lock is free.  Moreover, if the operation being locked over is trivial, the lock can add a very high level of overhead.  This is why things like Interlocked.Increment() perform so well, instead of locking just to perform an increment, we perform the increment with an atomic, lockless method. As with all things performance related, it’s important to profile before jumping to the conclusion that you should optimize everything in your path.  If your profiling shows that locking is causing a high level of waiting in your application, then it’s time to consider lighter alternatives such as Interlocked. CompareExchange() – Exchange existing value if equal some value So let’s look at how we could use CompareExchange() to solve our problem above.  The general syntax of CompareExchange() is: T CompareExchange<T>(ref T location, T newValue, T expectedValue) If the value in location == expectedValue, then newValue is exchanged.  Either way, the value in location (before exchange) is returned. Actually, CompareExchange() is not one method, but a family of overloaded methods that can take int, long, float, double, pointers, or references.  It cannot take other value types (that is, can’t CompareExchange() two DateTime instances directly).  Also keep in mind that the version that takes any reference type (the generic overload) only checks for reference equality, it does not call any overridden Equals(). So how does this help us?  Well, we can grab the current total, and exchange the new value if total hasn’t changed.  This would look like this: 1: // grab the snapshot 2: double current = total; 3:  4: // if the total hasn’t changed since I grabbed the snapshot, then 5: // set it to the new total 6: Interlocked.CompareExchange(ref total, current + next, current); So what the code above says is: if the amount in total (1st arg) is the same as the amount in current (3rd arg), then set total to current + next (2nd arg).  This check and exchange pair is atomic (and thus thread-safe). This works if total is the same as our snapshot in current, but the problem, is what happens if they aren’t the same?  Well, we know that in either case we will get the previous value of total (before the exchange), back as a result.  Thus, we can test this against our snapshot to see if it was the value we expected: 1: // if the value returned is != current, then our snapshot must be out of date 2: // which means we didn't (and shouldn't) apply current + next 3: if (Interlocked.CompareExchange(ref total, current + next, current) != current) 4: { 5: // ooops, total was not equal to our snapshot in current, what should we do??? 6: } So what do we do if we fail?  That’s up to you and the problem you are trying to solve.  It’s possible you would decide to abort the whole transaction, or perhaps do a lightweight spin and try again.  Let’s try that: 1: double current = total; 2:  3: // make first attempt... 4: if (Interlocked.CompareExchange(ref total, current + i, current) != current) 5: { 6: // if we fail, go into a spin wait, spin, and try again until succeed 7: var spinner = new SpinWait(); 8:  9: do 10: { 11: spinner.SpinOnce(); 12: current = total; 13: } 14: while (Interlocked.CompareExchange(ref total, current + i, current) != current); 15: } 16:  This is not trivial code, but it illustrates a possible use of CompareExchange().  What we are doing is first checking to see if we succeed on the first try, and if so great!  If not, we create a SpinWait and then repeat the process of SpinOnce(), grab a fresh snapshot, and repeat until CompareExchnage() succeeds.  You may wonder why not a simple do-while here, and the reason it’s more efficient to only create the SpinWait until we absolutely know we need one, for optimal efficiency. Though not as simple (or maintainable) as a simple lock, this will perform better in many situations.  Comparing an unlocked (and wrong) version, a version using lock, and the Interlocked of the code, we get the following average times for multiple iterations of adding the sum of 100,000 numbers: 1: Unlocked money average time: 2.1 ms 2: Locked money average time: 5.1 ms 3: Interlocked money average time: 3 ms So the Interlocked.CompareExchange(), while heavier to code, came in lighter than the lock, offering a good compromise of safety and performance when we need to reduce contention. CompareExchange() - it’s not just for adding stuff… So that was one simple use of CompareExchange() in the context of adding double values -- which meant we couldn’t have used the simpler Interlocked.Add() -- but it has other uses as well. If you think about it, this really works anytime you want to create something new based on a current value without using a full lock.  For example, you could use it to create a simple lazy instantiation implementation.  In this case, we want to set the lazy instance only if the previous value was null: 1: public static class Lazy<T> where T : class, new() 2: { 3: private static T _instance; 4:  5: public static T Instance 6: { 7: get 8: { 9: // if current is null, we need to create new instance 10: if (_instance == null) 11: { 12: // attempt create, it will only set if previous was null 13: Interlocked.CompareExchange(ref _instance, new T(), (T)null); 14: } 15:  16: return _instance; 17: } 18: } 19: } So, if _instance == null, this will create a new T() and attempt to exchange it with _instance.  If _instance is not null, then it does nothing and we discard the new T() we created. This is a way to create lazy instances of a type where we are more concerned about locking overhead than creating an accidental duplicate which is not used.  In fact, the BCL implementation of Lazy<T> offers a similar thread-safety choice for Publication thread safety, where it will not guarantee only one instance was created, but it will guarantee that all readers get the same instance.  Another possible use would be in concurrent collections.  Let’s say, for example, that you are creating your own brand new super stack that uses a linked list paradigm and is “lock free”.  We could use Interlocked.CompareExchange() to be able to do a lockless Push() which could be more efficient in multi-threaded applications where several threads are pushing and popping on the stack concurrently. Yes, there are already concurrent collections in the BCL (in .NET 4.0 as part of the TPL), but it’s a fun exercise!  So let’s assume we have a node like this: 1: public sealed class Node<T> 2: { 3: // the data for this node 4: public T Data { get; set; } 5:  6: // the link to the next instance 7: internal Node<T> Next { get; set; } 8: } Then, perhaps, our stack’s Push() operation might look something like: 1: public sealed class SuperStack<T> 2: { 3: private volatile T _head; 4:  5: public void Push(T value) 6: { 7: var newNode = new Node<int> { Data = value, Next = _head }; 8:  9: if (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next) 10: { 11: var spinner = new SpinWait(); 12:  13: do 14: { 15: spinner.SpinOnce(); 16: newNode.Next = _head; 17: } 18: while (Interlocked.CompareExchange(ref _head, newNode, newNode.Next) != newNode.Next); 19: } 20: } 21:  22: // ... 23: } Notice a similar paradigm here as with adding our doubles before.  What we are doing is creating the new Node with the data to push, and with a Next value being the original node referenced by _head.  This will create our stack behavior (LIFO – Last In, First Out).  Now, we have to set _head to now refer to the newNode, but we must first make sure it hasn’t changed! So we check to see if _head has the same value we saved in our snapshot as newNode.Next, and if so, we set _head to newNode.  This is all done atomically, and the result is _head’s original value, as long as the original value was what we assumed it was with newNode.Next, then we are good and we set it without a lock!  If not, we SpinWait and try again. Once again, this is much lighter than locking in highly parallelized code with lots of contention.  If I compare the method above with a similar class using lock, I get the following results for pushing 100,000 items: 1: Locked SuperStack average time: 6 ms 2: Interlocked SuperStack average time: 4.5 ms So, once again, we can get more efficient than a lock, though there is the cost of added code complexity.  Fortunately for you, most of the concurrent collection you’d ever need are already created for you in the System.Collections.Concurrent (here) namespace – for more information, see my Little Wonders – The Concurent Collections Part 1 (here), Part 2 (here), and Part 3 (here). Summary We’ve seen before how the Interlocked class can be used to safely and efficiently add, increment, decrement, read, and exchange values in a multi-threaded environment.  In addition to these, Interlocked CompareExchange() can be used to perform more complex logic without the need of a lock when lock contention is a concern. The added efficiency, though, comes at the cost of more complex code.  As such, the standard lock is often sufficient for most thread-safety needs.  But if profiling indicates you spend a lot of time waiting for locks, or if you just need a lock for something simple such as an increment, decrement, read, exchange, etc., then consider using the Interlocked class’s methods to reduce wait. Technorati Tags: C#,CSharp,.NET,Little Wonders,Interlocked,CompareExchange,threading,concurrency

  Read the article

• Adding Polynomials (Linked Lists)......Bug Help

  - by Brian

  I have written a program that creates nodes that in this class are parts of polynomials and then the two polynomials get added together to become one polynomial (list of nodes). All my code compiles so the only problem I am having is that the nodes are not inserting into the polynomial via the insert method I have in polynomial.java and when running the program it does create nodes and displays them in the 2x^2 format but when it comes to add the polynomials together it displays o as the polynomials, so if anyone can figure out whats wrong and what I can do to fix it it would be much appreciated. Here is the code: import java.util.Scanner; class Polynomial{ public termNode head; public Polynomial() { head = null; } public boolean isEmpty() { return (head == null); } public void display() { if (head == null) System.out.print("0"); else for(termNode cur = head; cur != null; cur = cur.getNext()) { System.out.println(cur); } } public void insert(termNode newNode) { termNode prev = null; termNode cur = head; while (cur!=null && (newNode.compareTo(cur)<0)) { prev = null; cur = cur.getNext(); } if (prev == null) { newNode.setNext(head); head = newNode; } else { newNode.setNext(cur); prev.setNext(newNode); } } public void readPolynomial(Scanner kb) { boolean done = false; double coefficient; int exponent; termNode term; head = null; //UNLINK ANY PREVIOUS POLYNOMIAL System.out.println("Enter 0 and 0 to end."); System.out.print("coefficient: "); coefficient = kb.nextDouble(); System.out.println(coefficient); System.out.print("exponent: "); exponent = kb.nextInt(); System.out.println(exponent); done = (coefficient == 0 && exponent == 0); while(!done) { Polynomial poly = new Polynomial(); term = new termNode(coefficient,exponent); System.out.println(term); poly.insert(term); System.out.println("Enter 0 and 0 to end."); System.out.print("coefficient: "); coefficient = kb.nextDouble(); System.out.println(coefficient); System.out.print("exponent: "); exponent = kb.nextInt(); System.out.println(exponent); done = (coefficient==0 && exponent==0); } } public static Polynomial add(Polynomial p, Polynomial q) { Polynomial r = new Polynomial(); double coefficient; int exponent; termNode first = p.head; termNode second = q.head; termNode sum = r.head; termNode term; while (first != null && second != null) { if (first.getExp() == second.getExp()) { if (first.getCoeff() != 0 && second.getCoeff() != 0); { double addCoeff = first.getCoeff() + second.getCoeff(); term = new termNode(addCoeff,first.getExp()); sum.setNext(term); first.getNext(); second.getNext(); } } else if (first.getExp() < second.getExp()) { sum.setNext(second); term = new termNode(second.getCoeff(),second.getExp()); sum.setNext(term); second.getNext(); } else { sum.setNext(first); term = new termNode(first.getNext()); sum.setNext(term); first.getNext(); } } while (first != null) { sum.setNext(first); } while (second != null) { sum.setNext(second); } return r; } } Here is my Node class: class termNode implements Comparable { private int exp; private double coeff; private termNode next; public termNode(double coefficient, int exponent) { coeff = coefficient; exp = exponent; next = null; } public termNode(termNode inTermNode) { coeff = inTermNode.coeff; exp = inTermNode.exp; } public void setData(double coefficient, int exponent) { coefficient = coeff; exponent = exp; } public double getCoeff() { return coeff; } public int getExp() { return exp; } public void setNext(termNode link) { next = link; } public termNode getNext() { return next; } public String toString() { if (exp == 0) { return(coeff + " "); } else if (exp == 1) { return(coeff + "x"); } else { return(coeff + "x^" + exp); } } public int compareTo(Object other) { if(exp ==((termNode) other).exp) return 0; else if(exp < ((termNode) other).exp) return -1; else return 1; } } And here is my Test class to run the program. import java.util.Scanner; class PolyTest{ public static void main(String [] args) { Scanner kb = new Scanner(System.in); Polynomial r; Polynomial p = new Polynomial(); System.out.println("Enter first polynomial."); p.readPolynomial(kb); Polynomial q = new Polynomial(); System.out.println(); System.out.println("Enter second polynomial."); q.readPolynomial(kb); r = Polynomial.add(p,q); System.out.println(); System.out.print("The sum of "); p.display(); System.out.print(" and "); q.display(); System.out.print(" is "); r.display(); } }

  Read the article

• Unexpected ArrayIndexOutOfBoundsException in JavaFX application, refering to no array

  - by Eugene

  I have the following code: public void setContent(Importer3D importer) { if (DEBUG) { System.out.println("Initialization of Mesh's arrays"); } coords = importer.getCoords(); texCoords = importer.getTexCoords(); faces = importer.getFaces(); if (DEBUG) { System.out.println("Applying Mesh's arrays"); } mesh = new TriangleMesh(); mesh.getPoints().setAll(coords); mesh.getTexCoords().setAll(texCoords); mesh.getFaces().setAll(faces); if (DEBUG) { System.out.println("Initialization of the material"); } initMaterial(); if (DEBUG) { System.out.println("Setting the MeshView"); } meshView.setMesh(mesh); meshView.setMaterial(material); meshView.setDrawMode(DrawMode.FILL); if (DEBUG) { System.out.println("Adding to 3D scene"); } root3d.getChildren().clear(); root3d.getChildren().add(meshView); if (DEBUG) { System.out.println("3D model is ready!"); } } The Imporeter3D class part: private void load(File file) { stlLoader = new STLLoader(file); } public float[] getCoords() { return stlLoader.getCoords(); } public float[] getTexCoords() { return stlLoader.getTexCoords(); } public int[] getFaces() { return stlLoader.getFaces(); } The STLLoader: public class STLLoader{ public STLLoader(File file) { stlFile = new STLFile(file); loadManager = stlFile.loadManager; pointsArray = new PointsArray(stlFile); texCoordsArray = new TexCoordsArray(); } public float[] getCoords() { return pointsArray.getPoints(); } public float[] getTexCoords() { return texCoordsArray.getTexCoords(); } public int[] getFaces() { return pointsArray.getFaces(); } private STLFile stlFile; private PointsArray pointsArray; private TexCoordsArray texCoordsArray; private FacesArray facesArray; public SimpleBooleanProperty finished = new SimpleBooleanProperty(false); public LoadManager loadManager;} PointsArray file: public class PointsArray { public PointsArray(STLFile stlFile) { this.stlFile = stlFile; initPoints(); } private void initPoints() { ArrayList<Double> pointsList = stlFile.getPoints(); ArrayList<Double> uPointsList = new ArrayList<>(); faces = new int[pointsList.size()*2]; int n = 0; for (Double d : pointsList) { if (uPointsList.indexOf(d) == -1) { uPointsList.add(d); } faces[n] = uPointsList.indexOf(d); faces[++n] = 0; n++; } int i = 0; points = new float[uPointsList.size()]; for (Double d : uPointsList) { points[i] = d.floatValue(); i++; } } public float[] getPoints() { return points; } public int[] getFaces() { return faces; } private float[] points; private int[] faces; private STLFile stlFile; public static boolean DEBUG = true; } And STLFile: ArrayList<Double> coords = new ArrayList<>(); double temp; private void readV(STLParser parser) { for (int n = 0; n < 3; n++) { if(!(parser.ttype==STLParser.TT_WORD && parser.sval.equals("vertex"))) { System.err.println("Format Error:expecting 'vertex' on line " + parser.lineno()); } else { if (parser.getNumber()) { temp = parser.nval; coords.add(temp); if(DEBUG) { System.out.println("Vertex:"); System.out.print("X=" + temp + " "); } if (parser.getNumber()) { temp = parser.nval; coords.add(temp); if(DEBUG) { System.out.print("Y=" + temp + " "); } if (parser.getNumber()) { temp = parser.nval; coords.add(temp); if(DEBUG) { System.out.println("Z=" + temp + " "); } readEOL(parser); } else System.err.println("Format Error: expecting coordinate on line " + parser.lineno()); } else System.err.println("Format Error: expecting coordinate on line " + parser.lineno()); } else System.err.println("Format Error: expecting coordinate on line " + parser.lineno()); } if (n < 2) { try { parser.nextToken(); } catch (IOException e) { System.err.println("IO Error on line " + parser.lineno() + ": " + e.getMessage()); } } } } public ArrayList<Double> getPoints() { return coords; } As a result of all of this code, I expected to get 3d model in MeshView. But the present result is very strange: everything works and in DEBUG mode I get 3d model is ready! from setContent(), and then unexpected ArrayIndexOutOfBoundsException: File readed Initialization of Mesh's arrays Applying Mesh's arrays Initialization of the material Setting the MeshView Adding to 3D scene 3D model is ready! java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 32252 at com.sun.javafx.collections.ObservableFloatArrayImpl.rangeCheck(ObservableFloatArrayImpl.java:276) at com.sun.javafx.collections.ObservableFloatArrayImpl.get(ObservableFloatArrayImpl.java:184) at javafx.scene.shape.TriangleMesh.computeBounds(TriangleMesh.java:262) at javafx.scene.shape.MeshView.impl_computeGeomBounds(MeshView.java:151) at javafx.scene.Node.updateGeomBounds(Node.java:3497) at javafx.scene.Node.getGeomBounds(Node.java:3450) at javafx.scene.Node.getLocalBounds(Node.java:3432) at javafx.scene.Node.updateTxBounds(Node.java:3510) at javafx.scene.Node.getTransformedBounds(Node.java:3350) at javafx.scene.Node.updateBounds(Node.java:516) at javafx.scene.Parent.updateBounds(Parent.java:1668) at javafx.scene.SubScene.updateBounds(SubScene.java:556) at javafx.scene.Parent.updateBounds(Parent.java:1668) at javafx.scene.Parent.updateBounds(Parent.java:1668) at javafx.scene.Parent.updateBounds(Parent.java:1668) at javafx.scene.Parent.updateBounds(Parent.java:1668) at javafx.scene.Parent.updateBounds(Parent.java:1668) at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2309) at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:329) at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:479) at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:459) at com.sun.javafx.tk.quantum.QuantumToolkit$13.run(QuantumToolkit.java:326) at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) at com.sun.glass.ui.win.WinApplication.access$300(WinApplication.java:39) at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:101) at java.lang.Thread.run(Thread.java:724) Exception in thread "JavaFX Application Thread" java.lang.ArrayIndexOutOfBoundsException: Array index out of range: 32252 at com.sun.javafx.collections.ObservableFloatArrayImpl.rangeCheck(ObservableFloatArrayImpl.java:276) at com.sun.javafx.collections.ObservableFloatArrayImpl.get(ObservableFloatArrayImpl.java:184) The stranger thing is that this stack doesn't stop until I close the program. And moreover it doesn't point to any my array. What is this? And why does it happen?

  Read the article

• Incorrect output on changing sequence of declarations

  - by max

  Writing C++ code to implement Sutherland-Hodgeman polygon clipping. This order of declaration of these 2 statements gives correct output, reverse does not. int numberOfVertices = 5; Point pointList[] = { {50,50}, {200,300}, {310,110}, {130,90}, {70,40} }; I am passing the polygon vertex set to clippers in order - LEFT, RIGHT, TOP, BOTTOM. The exact error which comes when the declarations are reversed is that the bottom clipper, produces an empty set of vertices so no polygon is displayed after clipping. Correct: Incorrent: Confirmed by outputting the number of vertices produced after each pass: Correct: Incorrect: What is the reason for this error? Code: #include <iostream> #include <GL/glut.h> #define MAXVERTICES 10 #define LEFT 0 #define RIGHT 1 #define TOP 2 #define BOTTOM 3 using namespace std; /* Clipping window */ struct Window { double xmin; double xmax; double ymin; double ymax; }; struct Point { double x; double y; }; /* If I interchange these two lines, the code doesn't work. */ /**************/ int numberOfVertices = 5; Point pointList[] = { {50,50}, {200,300}, {310,110}, {130,90}, {70,40} }; /**************/ const Window w = { 100, 400, 60, 200 }; /* Checks whether a point is inside or outside a window side */ int isInside(Point p, int side) { switch(side) { case LEFT: return p.x >= w.xmin; case RIGHT: return p.x <= w.xmax; case TOP: return p.y <= w.ymax; case BOTTOM: return p.y >= w.ymin; } } /* Calculates intersection of a segment and a window side */ Point intersection(Point p1, Point p2, int side) { Point temp; double slope, intercept; bool infinite; /* Find slope and intercept of segment, taking care of inf slope */ if(p2.x - p1.x != 0) { slope = (p2.y - p1.y) / (p2.x - p1.x); infinite = false; } else { infinite = true; } intercept = p1.y - p1.x * slope; /* Calculate intersections */ switch(side) { case LEFT: temp.x = w.xmin; temp.y = temp.x * slope + intercept; break; case RIGHT: temp.x = w.xmax; temp.y = temp.x * slope + intercept; break; case TOP: temp.y = w.ymax; temp.x = infinite ? p1.x : (temp.y - intercept) / slope; break; case BOTTOM: temp.y = w.ymin; temp.x = infinite ? p1.x : (temp.y - intercept) / slope; break; } return temp; } /* Clips polygon against a side, updating the point list (called once for each side) */ void clipAgainstSide(int sideToClip) { int i, j=0; Point s,p; Point outputList[MAXVERTICES]; /* Main algorithm */ s = pointList[numberOfVertices-1]; for(i=0 ; i<numberOfVertices ; i++) { p = pointList[i]; if(isInside(p, sideToClip)) { /* p inside */ if(!isInside(s, sideToClip)) { /* p inside, s outside */ outputList[j] = intersection(p, s, sideToClip); j++; } outputList[j] = p; j++; } else if(isInside(s, sideToClip)) { /* s inside, p outside */ outputList[j] = intersection(s, p, sideToClip); j++; } s = p; } /* Updating number of points and point list */ numberOfVertices = j; /* ERROR: In last call with BOTTOM argument, numberOfVertices becomes 0 */ /* all earlier 3 calls have correct output */ cout<<numberOfVertices<<endl; for(i=0 ; i<numberOfVertices ; i++) { pointList[i] = outputList[i]; } } void SutherlandHodgemanPolygonClip() { clipAgainstSide(LEFT); clipAgainstSide(RIGHT); clipAgainstSide(TOP); clipAgainstSide(BOTTOM); } void init() { glClearColor(1,1,1,0); glMatrixMode(GL_PROJECTION); gluOrtho2D(0,1000,0,500); } void display() { glClear(GL_COLOR_BUFFER_BIT); /* Displaying ORIGINAL box and polygon */ glColor3f(0,0,1); glBegin(GL_LINE_LOOP); glVertex2i(w.xmin, w.ymin); glVertex2i(w.xmin, w.ymax); glVertex2i(w.xmax, w.ymax); glVertex2i(w.xmax, w.ymin); glEnd(); glColor3f(1,0,0); glBegin(GL_LINE_LOOP); for(int i=0 ; i<numberOfVertices ; i++) { glVertex2i(pointList[i].x, pointList[i].y); } glEnd(); /* Clipping */ SutherlandHodgemanPolygonClip(); /* Displaying CLIPPED box and polygon, 500px right */ glColor3f(0,0,1); glBegin(GL_LINE_LOOP); glVertex2i(w.xmin+500, w.ymin); glVertex2i(w.xmin+500, w.ymax); glVertex2i(w.xmax+500, w.ymax); glVertex2i(w.xmax+500, w.ymin); glEnd(); glColor3f(1,0,0); glBegin(GL_LINE_LOOP); for(int i=0 ; i<numberOfVertices ; i++) { glVertex2i(pointList[i].x+500, pointList[i].y); } glEnd(); glFlush(); } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(1000,500); glutCreateWindow("Sutherland-Hodgeman polygon clipping"); init(); glutDisplayFunc(display); glutMainLoop(); return 0; }

  Read the article

• Announcing release of ASP.NET MVC 3, IIS Express, SQL CE 4, Web Farm Framework, Orchard, WebMatrix

  - by ScottGu

  I’m excited to announce the release today of several products: ASP.NET MVC 3 NuGet IIS Express 7.5 SQL Server Compact Edition 4 Web Deploy and Web Farm Framework 2.0 Orchard 1.0 WebMatrix 1.0 The above products are all free. They build upon the .NET 4 and VS 2010 release, and add a ton of additional value to ASP.NET (both Web Forms and MVC) and the Microsoft Web Server stack. ASP.NET MVC 3 Today we are shipping the final release of ASP.NET MVC 3.  You can download and install ASP.NET MVC 3 here.  The ASP.NET MVC 3 source code (released under an OSI-compliant open source license) can also optionally be downloaded here. ASP.NET MVC 3 is a significant update that brings with it a bunch of great features.  Some of the improvements include: Razor ASP.NET MVC 3 ships with a new view-engine option called “Razor” (in addition to continuing to support/enhance the existing .aspx view engine).  Razor minimizes the number of characters and keystrokes required when writing a view template, and enables a fast, fluid coding workflow. Unlike most template syntaxes, with Razor you do not need to interrupt your coding to explicitly denote the start and end of server blocks within your HTML. The Razor parser is smart enough to infer this from your code. This enables a compact and expressive syntax which is clean, fast and fun to type.  You can learn more about Razor from some of the blog posts I’ve done about it over the last 6 months Introducing Razor New @model keyword in Razor Layouts with Razor Server-Side Comments with Razor Razor’s @: and <text> syntax Implicit and Explicit code nuggets with Razor Layouts and Sections with Razor Today’s release supports full code intellisense support for Razor (both VB and C#) with Visual Studio 2010 and the free Visual Web Developer 2010 Express. JavaScript Improvements ASP.NET MVC 3 enables richer JavaScript scenarios and takes advantage of emerging HTML5 capabilities. The AJAX and Validation helpers in ASP.NET MVC 3 now use an Unobtrusive JavaScript based approach.  Unobtrusive JavaScript avoids injecting inline JavaScript into HTML, and enables cleaner separation of behavior using the new HTML 5 “data-“ attribute convention (which conveniently works on older browsers as well – including IE6). This keeps your HTML tight and clean, and makes it easier to optionally swap out or customize JS libraries.  ASP.NET MVC 3 now includes built-in support for posting JSON-based parameters from client-side JavaScript to action methods on the server.  This makes it easier to exchange data across the client and server, and build rich JavaScript front-ends.  We think this capability will be particularly useful going forward with scenarios involving client templates and data binding (including the jQuery plugins the ASP.NET team recently contributed to the jQuery project).  Previous releases of ASP.NET MVC included the core jQuery library.  ASP.NET MVC 3 also now ships the jQuery Validate plugin (which our validation helpers use for client-side validation scenarios).  We are also now shipping and including jQuery UI by default as well (which provides a rich set of client-side JavaScript UI widgets for you to use within projects). Improved Validation ASP.NET MVC 3 includes a bunch of validation enhancements that make it even easier to work with data. Client-side validation is now enabled by default with ASP.NET MVC 3 (using an onbtrusive javascript implementation).  Today’s release also includes built-in support for Remote Validation - which enables you to annotate a model class with a validation attribute that causes ASP.NET MVC to perform a remote validation call to a server method when validating input on the client. The validation features introduced within .NET 4’s System.ComponentModel.DataAnnotations namespace are now supported by ASP.NET MVC 3.  This includes support for the new IValidatableObject interface – which enables you to perform model-level validation, and allows you to provide validation error messages specific to the state of the overall model, or between two properties within the model.  ASP.NET MVC 3 also supports the improvements made to the ValidationAttribute class in .NET 4.  ValidationAttribute now supports a new IsValid overload that provides more information about the current validation context, such as what object is being validated.  This enables richer scenarios where you can validate the current value based on another property of the model.  We’ve shipped a built-in [Compare] validation attribute  with ASP.NET MVC 3 that uses this support and makes it easy out of the box to compare and validate two property values. You can use any data access API or technology with ASP.NET MVC.  This past year, though, we’ve worked closely with the .NET data team to ensure that the new EF Code First library works really well for ASP.NET MVC applications.  These two posts of mine cover the latest EF Code First preview and demonstrates how to use it with ASP.NET MVC 3 to enable easy editing of data (with end to end client+server validation support).  The final release of EF Code First will ship in the next few weeks. Today we are also publishing the first preview of a new MvcScaffolding project.  It enables you to easily scaffold ASP.NET MVC 3 Controllers and Views, and works great with EF Code-First (and is pluggable to support other data providers).  You can learn more about it – and install it via NuGet today - from Steve Sanderson’s MvcScaffolding blog post. Output Caching Previous releases of ASP.NET MVC supported output caching content at a URL or action-method level. With ASP.NET MVC V3 we are also enabling support for partial page output caching – which allows you to easily output cache regions or fragments of a response as opposed to the entire thing.  This ends up being super useful in a lot of scenarios, and enables you to dramatically reduce the work your application does on the server.  The new partial page output caching support in ASP.NET MVC 3 enables you to easily re-use cached sub-regions/fragments of a page across multiple URLs on a site.  It supports the ability to cache the content either on the web-server, or optionally cache it within a distributed cache server like Windows Server AppFabric or memcached. I’ll post some tutorials on my blog that show how to take advantage of ASP.NET MVC 3’s new output caching support for partial page scenarios in the future. Better Dependency Injection ASP.NET MVC 3 provides better support for applying Dependency Injection (DI) and integrating with Dependency Injection/IOC containers. With ASP.NET MVC 3 you no longer need to author custom ControllerFactory classes in order to enable DI with Controllers.  You can instead just register a Dependency Injection framework with ASP.NET MVC 3 and it will resolve dependencies not only for Controllers, but also for Views, Action Filters, Model Binders, Value Providers, Validation Providers, and Model Metadata Providers that you use within your application. This makes it much easier to cleanly integrate dependency injection within your projects. Other Goodies ASP.NET MVC 3 includes dozens of other nice improvements that help to both reduce the amount of code you write, and make the code you do write cleaner.  Here are just a few examples: Improved New Project dialog that makes it easy to start new ASP.NET MVC 3 projects from templates. Improved Add->View Scaffolding support that enables the generation of even cleaner view templates. New ViewBag property that uses .NET 4’s dynamic support to make it easy to pass late-bound data from Controllers to Views. Global Filters support that allows specifying cross-cutting filter attributes (like [HandleError]) across all Controllers within an app. New [AllowHtml] attribute that allows for more granular request validation when binding form posted data to models. Sessionless controller support that allows fine grained control over whether SessionState is enabled on a Controller. New ActionResult types like HttpNotFoundResult and RedirectPermanent for common HTTP scenarios. New Html.Raw() helper to indicate that output should not be HTML encoded. New Crypto helpers for salting and hashing passwords. And much, much more… Learn More about ASP.NET MVC 3 We will be posting lots of tutorials and samples on the http://asp.net/mvc site in the weeks ahead.  Below are two good ASP.NET MVC 3 tutorials available on the site today: Build your First ASP.NET MVC 3 Application: VB and C# Building the ASP.NET MVC 3 Music Store We’ll post additional ASP.NET MVC 3 tutorials and videos on the http://asp.net/mvc site in the future. Visit it regularly to find new tutorials as they are published. How to Upgrade Existing Projects ASP.NET MVC 3 is compatible with ASP.NET MVC 2 – which means it should be easy to update existing MVC projects to ASP.NET MVC 3.  The new features in ASP.NET MVC 3 build on top of the foundational work we’ve already done with the MVC 1 and MVC 2 releases – which means that the skills, knowledge, libraries, and books you’ve acquired are all directly applicable with the MVC 3 release.  MVC 3 adds new features and capabilities – it doesn’t obsolete existing ones. You can upgrade existing ASP.NET MVC 2 projects by following the manual upgrade steps in the release notes.  Alternatively, you can use this automated ASP.NET MVC 3 upgrade tool to easily update your  existing projects. Localized Builds Today’s ASP.NET MVC 3 release is available in English.  We will be releasing localized versions of ASP.NET MVC 3 (in 9 languages) in a few days.  I’ll blog pointers to the localized downloads once they are available. NuGet Today we are also shipping NuGet – a free, open source, package manager that makes it easy for you to find, install, and use open source libraries in your projects. It works with all .NET project types (including ASP.NET Web Forms, ASP.NET MVC, WPF, WinForms, Silverlight, and Class Libraries).  You can download and install it here. NuGet enables developers who maintain open source projects (for example, .NET projects like Moq, NHibernate, Ninject, StructureMap, NUnit, Windsor, Raven, Elmah, etc) to package up their libraries and register them with an online gallery/catalog that is searchable.  The client-side NuGet tools – which include full Visual Studio integration – make it trivial for any .NET developer who wants to use one of these libraries to easily find and install it within the project they are working on. NuGet handles dependency management between libraries (for example: library1 depends on library2). It also makes it easy to update (and optionally remove) libraries from your projects later. It supports updating web.config files (if a package needs configuration settings). It also allows packages to add PowerShell scripts to a project (for example: scaffold commands). Importantly, NuGet is transparent and clean – and does not install anything at the system level. Instead it is focused on making it easy to manage libraries you use with your projects. Our goal with NuGet is to make it as simple as possible to integrate open source libraries within .NET projects.  NuGet Gallery This week we also launched a beta version of the http://nuget.org web-site – which allows anyone to easily search and browse an online gallery of open source packages available via NuGet.  The site also now allows developers to optionally submit new packages that they wish to share with others.  You can learn more about how to create and share a package here. There are hundreds of open-source .NET projects already within the NuGet Gallery today.  We hope to have thousands there in the future. IIS Express 7.5 Today we are also shipping IIS Express 7.5.  IIS Express is a free version of IIS 7.5 that is optimized for developer scenarios.  It works for both ASP.NET Web Forms and ASP.NET MVC project types. We think IIS Express combines the ease of use of the ASP.NET Web Server (aka Cassini) currently built-into Visual Studio today with the full power of IIS.  Specifically: It’s lightweight and easy to install (less than 5Mb download and a quick install) It does not require an administrator account to run/debug applications from Visual Studio It enables a full web-server feature set – including SSL, URL Rewrite, and other IIS 7.x modules It supports and enables the same extensibility model and web.config file settings that IIS 7.x support It can be installed side-by-side with the full IIS web server as well as the ASP.NET Development Server (they do not conflict at all) It works on Windows XP and higher operating systems – giving you a full IIS 7.x developer feature-set on all Windows OS platforms IIS Express (like the ASP.NET Development Server) can be quickly launched to run a site from a directory on disk.  It does not require any registration/configuration steps. This makes it really easy to launch and run for development scenarios.  You can also optionally redistribute IIS Express with your own applications if you want a lightweight web-server.  The standard IIS Express EULA now includes redistributable rights. Visual Studio 2010 SP1 adds support for IIS Express.  Read my VS 2010 SP1 and IIS Express blog post to learn more about what it enables.  SQL Server Compact Edition 4 Today we are also shipping SQL Server Compact Edition 4 (aka SQL CE 4).  SQL CE is a free, embedded, database engine that enables easy database storage. No Database Installation Required SQL CE does not require you to run a setup or install a database server in order to use it.  You can simply copy the SQL CE binaries into the \bin directory of your ASP.NET application, and then your web application can use it as a database engine.  No setup or extra security permissions are required for it to run. You do not need to have an administrator account on the machine. Just copy your web application onto any server and it will work. This is true even of medium-trust applications running in a web hosting environment. SQL CE runs in-memory within your ASP.NET application and will start-up when you first access a SQL CE database, and will automatically shutdown when your application is unloaded.  SQL CE databases are stored as files that live within the \App_Data folder of your ASP.NET Applications. Works with Existing Data APIs SQL CE 4 works with existing .NET-based data APIs, and supports a SQL Server compatible query syntax.  This means you can use existing data APIs like ADO.NET, as well as use higher-level ORMs like Entity Framework and NHibernate with SQL CE.  This enables you to use the same data programming skills and data APIs you know today. Supports Development, Testing and Production Scenarios SQL CE can be used for development scenarios, testing scenarios, and light production usage scenarios.  With the SQL CE 4 release we’ve done the engineering work to ensure that SQL CE won’t crash or deadlock when used in a multi-threaded server scenario (like ASP.NET).  This is a big change from previous releases of SQL CE – which were designed for client-only scenarios and which explicitly blocked running in web-server environments.  Starting with SQL CE 4 you can use it in a web-server as well. There are no license restrictions with SQL CE.  It is also totally free. Tooling Support with VS 2010 SP1 Visual Studio 2010 SP1 adds support for SQL CE 4 and ASP.NET Projects.  Read my VS 2010 SP1 and SQL CE 4 blog post to learn more about what it enables.  Web Deploy and Web Farm Framework 2.0 Today we are also releasing Microsoft Web Deploy V2 and Microsoft Web Farm Framework V2.  These services provide a flexible and powerful way to deploy ASP.NET applications onto either a single server, or across a web farm of machines. You can learn more about these capabilities from my previous blog posts on them: Introducing the Microsoft Web Farm Framework Automating Deployment with Microsoft Web Deploy Visit the http://iis.net website to learn more and install them. Both are free. Orchard 1.0 Today we are also releasing Orchard v1.0.  Orchard is a free, open source, community based project.  It provides Content Management System (CMS) and Blogging System support out of the box, and makes it possible to easily create and manage web-sites without having to write code (site owners can customize a site through the browser-based editing tools built-into Orchard).  Read these tutorials to learn more about how you can setup and manage your own Orchard site. Orchard itself is built as an ASP.NET MVC 3 application using Razor view templates (and by default uses SQL CE 4 for data storage).  Developers wishing to extend an Orchard site with custom functionality can open and edit it as a Visual Studio project – and add new ASP.NET MVC Controllers/Views to it.  WebMatrix 1.0 WebMatrix is a new, free, web development tool from Microsoft that provides a suite of technologies that make it easier to enable website development.  It enables a developer to start a new site by browsing and downloading an app template from an online gallery of web applications (which includes popular apps like Umbraco, DotNetNuke, Orchard, WordPress, Drupal and Joomla).  Alternatively it also enables developers to create and code web sites from scratch. WebMatrix is task focused and helps guide developers as they work on sites.  WebMatrix includes IIS Express, SQL CE 4, and ASP.NET - providing an integrated web-server, database and programming framework combination.  It also includes built-in web publishing support which makes it easy to find and deploy sites to web hosting providers. You can learn more about WebMatrix from my Introducing WebMatrix blog post this summer.  Visit http://microsoft.com/web to download and install it today. Summary I’m really excited about today’s releases – they provide a bunch of additional value that makes web development with ASP.NET, Visual Studio and the Microsoft Web Server a lot better.  A lot of folks worked hard to share this with you today. On behalf of my whole team – we hope you enjoy them! Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

  Read the article

• Tulsa Dot Net Rocks

  - by dmccollough

  Carl Franklin & Richard Campbell of .NET Rocks are taking their show on the road and are going to make a stop in Tulsa Oklahoma on Wednesday April 28th, 2010. This event will be from 6:00 PM until 9:00 PM. This is a FREE EVENT, with FREE FOOD and FREE SWAG. They are also going to be bringing a special surprise guest speaker (It could be Scott Hanselman, Scott Guthrie, Don Box, Billy Hollis, Dan Appleman or …)   Broken Arrow North Auditorium 808 East College Street   Please visit the Tulsa Developers .NET web site for updated information as it becomes available.   Register by going to this link.

  Read the article

• No, iCloud Isn’t Backing Them All Up: How to Manage Photos on Your iPhone or iPad

  - by Chris Hoffman

  Are the photos you take with your iPhone or iPad backed up in case you lose your device? If you’re just relying on iCloud to manage your important memories, your photos may not be backed up at all. Apple’s iCloud has a photo-syncing feature in the form of “Photo Stream,” but Photo Stream doesn’t actually perform any long-term backups of your photos. iCloud’s Photo Backup Limitations Assuming you’ve set up iCloud on your iPhone or iPad, your device is using a feature called “Photo Stream” to automatically upload the photos you take to your iCloud storage and sync them across your devices. Unfortunately, there are some big limitations here. 1000 Photos: Photo Stream only backs up the latest 1000 photos. Do you have 1500 photos in your Camera Roll folder on your phone? If so, only the latest 1000 photos are stored in your iCloud account online. If you don’t have those photos backed up elsewhere, you’ll lose them when you lose your phone. If you have 1000 photos and take one more, the oldest photo will be removed from your iCloud Photo Stream. 30 Days: Apple also states that photos in your Photo Stream will be automatically deleted after 30 days “to give your devices plenty of time to connect and download them.” Some people report photos aren’t deleted after 30 days, but it’s clear you shouldn’t rely on iCloud for more than 30 days of storage. iCloud Storage Limits: Apple only gives you 5 GB of iCloud storage space for free, and this is shared between backups, documents, and all other iCloud data. This 5 GB can fill up pretty quickly. If your iCloud storage is full and you haven’t purchased any more storage more from Apple, your photos aren’t being backed up. Videos Aren’t Included: Photo Stream doesn’t include videos, so any videos you take aren’t automatically backed up. It’s clear that iCloud’s Photo Stream isn’t designed as a long-term way to store your photos, just a convenient way to access recent photos on all your devices before you back them up for real. iCloud’s Photo Stream is Designed for Desktop Backups If you have a Mac, you can launch iPhoto and enable the Automatic Import option under Photo Stream in its preferences pane. Assuming your Mac is on and connected to the Internet, iPhoto will automatically download photos from your photo stream and make local backups of them on your hard drive. You’ll then have to back up your photos manually so you don’t lose them if your Mac’s hard drive ever fails. If you have a Windows PC, you can install the iCloud Control Panel, which will create a Photo Stream folder on your PC. Your photos will be automatically downloaded to this folder and stored in it. You’ll want to back up your photos so you don’t lose them if your PC’s hard drive ever fails. Photo Stream is clearly designed to be used along with a desktop application. Photo Stream temporarily backs up your photos to iCloud so iPhoto or iCloud Control Panel can download them to your Mac or PC and make a local backup before they’re deleted. You could also use iTunes to sync your photos from your device to your PC or Mac, but we don’t really recommend it — you should never have to use iTunes. How to Actually Back Up All Your Photos Online So Photo Stream is actually pretty inconvenient — or, at least, it’s just a way to temporarily sync photos between your devices without storing them long-term. But what if you actually want to automatically back up your photos online without them being deleted automatically? The solution here is a third-party app that does this for you, offering the automatic photo uploads with long-term storage. There are several good services with apps in the App Store: Dropbox: Dropbox’s Camera Upload feature allows you to automatically upload the photos — and videos — you take to your Dropbox account. They’ll be easily accessible anywhere there’s a Dropbox app and you can get much more free Dropbox storage than you can iCloud storage. Dropbox will never automatically delete your old photos. Google+: Google+ offers photo and video backups with its Auto Upload feature, too. Photos will be stored in your Google+ Photos — formerly Picasa Web Albums — and will be marked as private by default so no one else can view them. Full-size photos will count against your free 15 GB of Google account storage space, but you can also choose to upload an unlimited amount of photos at a smaller resolution. Flickr: The Flickr app is no longer a mess. Flickr offers an Auto Upload feature for uploading full-size photos you take and free Flickr accounts offer a massive 1 TB of storage for you to store your photos. The massive amount of free storage alone makes Flickr worth a look. Use any of these services and you’ll get an online, automatic photo backup solution you can rely on. You’ll get a good chunk of free space, your photos will never be automatically deleted, and you can easily access them from any device. You won’t have to worry about storing local copies of your photos and backing them up manually. Apple should fix this mess and offer a better solution for long-term photo backup, especially considering the limitations aren’t immediately obvious to users. Until they do, third-party apps are ready to step in and take their place. You can also automatically back up your photos to the web on Android with Google+’s Auto Upload or Dropbox’s Camera Upload. Image Credit: Simon Yeo on Flickr     

  Read the article

• Delicious is Shutting Down. Here’s How to Migrate to Diigo Instead

  - by Trevor Bekolay

  Today we’ve learned that Yahoo is shutting down Delicious, a fairly popular online service that let you organize your bookmarks, so if you want to get your bookmarks out and migrate to another service, here’s how to do it. You can use the export tool to easily get a copy of your bookmarks, and then use that file to import into any number of places, including your regular browser bookmarks. We’ve done some research and found Diigo, a very similar tool to Delicious, which you can use instead Latest Features How-To Geek ETC The Complete List of iPad Tips, Tricks, and Tutorials The 50 Best Registry Hacks that Make Windows Better The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Exploring the Jungle Ruins Wallpaper Protect Your Privacy When Browsing with Chrome and Iron Browser Free Shipping Day is Friday, December 17, 2010 – National Free Shipping Day Find an Applicable Quote for Any Programming Situation Winter Theme for Windows 7 from Microsoft Score Free In-Flight Wi-Fi Courtesy of Google Chrome

  Read the article

• Here’s Two Android Tools That Can Help Cut Down Your Phone Bills

  - by Zainul Franciscus

  Have you been struggling to stay on top of your mobile bills ? With these Android applications, you can send free sms and monitor your mobile usage, so that you’ll never have to go over your monthly mobile allowance. To accomplish this, we will use two Android applications:  HeyWire for sending free local and international sms, and Droid Stats to monitor our monthly phone usage. Both of these applications are available for free from the Android market, so head over to the market, and install them when you are ready.How to Create an Easy Pixel Art Avatar in Photoshop or GIMPInternet Explorer 9 Released: Here’s What You Need To KnowHTG Explains: How Does Email Work?

  Read the article

• Support for Windows 2000 Professional and Server to be dropped

  - by Testas

  Windows 2000 Professional and Windows 2000 Server are approaching 10 years since their launch and both products will go out of support on July 13, 2010. Windows XP was launched back in 2001. While support for the product will continue, Service Pack 2 will go out of support on July 13, 2010. From that date onwards, Microsoft will no longer support or provide free security updates for Windows XP SP2.  Please install the free Service Pack 3 for Windows XP to have the most secure and supported Windows XP platform.Finally, Windows Vista with no Service Packs installed will end support on April 13 2010.  Please install the free Service Pack 2 for Windows Vista to have the most secure and supported Windows Vista platform.   This may have implications for older version of SQL Server that are installed on these products and you should assess whether it is time to upgrade   Chris

  Read the article

• Adding partitions to dual boot on Windows

  - by Bernard

  I am trying to install Ubuntu 12.04 along side Windows 7 on an HP mini 210 netbook. I have down loaded an iso image OK and got the installation program working but I am having problems with partitioning. I want to keep my Windows installation intact so I am following the 'Other' installation route. I have managed to shrink the main Windows partition down to 50GB leaving 250GB free space but I can't find a way of adding any extra partitions for Ubuntu. The free space gets listed by the installer as 'unusable' but on the graphic at the top its called 'free space'. If I select this and click 'Install Now' I get an error message: 'No root file system is defined'. I have tried clicking the Add, Change Delete and New Partition table buttons with the unusable partition selected and nothing happens. How do I define a root mount point when I do not have any Linux partitions?

  Read the article

• Chromium/Chrome tabs crashes on Ubuntu/Edubuntu 12.04.3

  - by Joakim Waern

  For some reason the tabs of Chromium and Chrome have started to crash (He's dead Jim) when running on Ubuntu or Edubuntu 12.04.3. It seems to happen only when I log in. I tried the browsers on Ubuntu 13.10 and everything worked fine. Any suggestions? Ps. The browser doesn't crash, just the tabs, and I can open new ones (but they also crash after a while). Here's the output command free on the terminal after a tab crash: total used free shared buffers cached Mem: 2041116 1722740 318376 0 2868 267256 -/+ buffers/cache: 1452616 588500 Swap: 2085884 104 2085780 Compared to the output before the crash: total used free shared buffers cached Mem: 2041116 1967108 74008 0 14632 253036 -/+ buffers/cache: 1699440 341676 Swap: 2085884 40 2085844

  Read the article

• Book review: SQL Server Transaction Log Management

  - by Hugo Kornelis

  It was an offer I could not resist. I was promised a free copy of one of the newest books from Red Gate Books , SQL Server Transaction Log Management (by Tony Davis and Gail Shaw ), with the caveat that I should write a review after reading it. Mind you, not a commercial, “make sure we sell more copies” kind of review, but a review of my actual thoughts. Yes, I got explicit permission to be my usual brutally honest self. A total win/win for me! First, I get a free book – and free is always good,...(read more)

  Read the article

• Opera 11 Adds Tab Stacking, Extensions, and More [Screenshot Tour]

  - by The Geek

  Opera 11 has just been released, with lots of great new features. Let’s take a quick tour through the best features for the world’s most alternate browser. If you’d rather see the new stuff in the form of a video, here’s the official Opera 11 release video. Otherwise, scroll down for all the screenshots. Latest Features How-To Geek ETC The Complete List of iPad Tips, Tricks, and Tutorials The 50 Best Registry Hacks that Make Windows Better The How-To Geek Holiday Gift Guide (Geeky Stuff We Like) LCD? LED? Plasma? The How-To Geek Guide to HDTV Technology The How-To Geek Guide to Learning Photoshop, Part 8: Filters Improve Digital Photography by Calibrating Your Monitor Free Shipping Day is Friday, December 17, 2010 – National Free Shipping Day Find an Applicable Quote for Any Programming Situation Winter Theme for Windows 7 from Microsoft Score Free In-Flight Wi-Fi Courtesy of Google Chrome Peaceful Winter Road at Sunset Wallpaper Everything You Ever Wanted to Know About Why Pac-Man’s Ghosts Move the Way They Do

  Read the article

• Manage Your Amazon S3 Account with CloudBerry Explorer

  - by Mysticgeek

  If you have an Amazon S3 account you’re using to backup your data, you might want an easy way to manage it. CloudBerry Explorer is a free app that runs on your desktop an provides an easy way to manage your S3 account. Installation and Setup Just download and install the application with the defaults. When the application launches you’ll be prompted to enter in your username and email to get a registration key. Or you can continue on by clicking Register later. Now you will want to set up your Amazon S3 account. Click on File \ Amazon S3 Accounts. Double-click on the New Account icon.   Next enter in your Amazon account Access and Secret keys, select SSL if you want, then click the Test Connection button. Provided everything was entered correctly, you’ll see the Connection Success screen, just close out of it. Browse and Manage files Once you have your account setup through the Explorer, you can start viewing and managing your files on S3. The left pane shows your S3 buckets and stored files, while the right side shows your local computer. This allows you to manage your files in your Amazon S3 buckets directly from your desktop! It’s very easy to use, and you can drag and drop files from your computer to the S3 account or vice versa. There is also the ability to transfer files between Amazon S3 accounts from within the explorer. Go into Tools and Content Types and you can control the file types by adding, removing, or editing them. If you end up messing something up along the lines, you can always select Reset to defaults and everything will be back to normal. There is a multiple tabbed view so you can easily keep track of your different accounts and local machine. It allows the ability to create new storage buckets directly in the Explorer. Or you can delete buckets as well… Different actions can be accessed from the toolbars or by right-clicking and selecting from the context menu. Here we see a cool option that lets you move your data inside Amazon S3. It is faster and doesn’t cost money by moving the files to your computer first, then to another account. However, if you want data moved to your local machine first, you have that option as well.   Not all features are available in the free version, and if it’s not, you’ll be prompted to purchase a license for the Pro version. We will have a comprehensive review of the Pro version in the near future.    If you ever need help with CloudBerry Explorer, go to Tools \ Diagnostics. It will run a quick diagnostics check and you can send the information to the CloudBerry team for assistance. Delete Files from Amazon S3 To delete a file from you Amazon S3 account, simply highlight the files or folder you want to get rid of then click Delete on the toolbar. You can also right-click the file and select Delete from the Context Menu. Click Yes to the confirmation dialog box… Then you can watch the progress as your files are deleted in the bottom section of the explorer. Conclusion CloudBerry Explorer free version has several neat features that will allow you easy and basic control over you Amazon S3 account. The free version may be enough for basic users, but power users will want to upgrade to the pro version, as it includes a lot more features. Using the free version allows you to get a feel for what CloudBerry Explorer has to offer, and is a good starting point. Keep in mind that Amazon S3 is introducing Reduced Redundancy Storage which will lower the price of data stored. The price drops from $0.15 per GB to only $0.10 per GB. If you’re a Windows Home Server user, check out our review of CloudBerry Online Backup 1.5 for WHS. Download CloudBerry Explorer Free for Amazon S3 Similar Articles Productive Geek Tips CloudBerry Online Backup 1.5 for Windows Home ServerReopen Closed Tabs in Internet ExplorerPreview and Purchase Ebooks with Kindle for PCTroubleshoot and Manage Addons in Internet Explorer 8Beginner Geek: Delete User Accounts in Windows 7 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 VMware Workstation 7 Google TV The iPod Revolution Ultimate Boot CD can help when disaster strikes Windows Firewall with Advanced Security – How To Guides Sculptris 1.0, 3D Drawing app AceStock, a Tiny Desktop Quote Monitor

  Read the article

• HTG Explains: What Is Open-Source Software and Why You Should Care

  - by Chris Hoffman

  Geeks often describe programs as being “open source” or “free software.” If you’re wondering exactly what these terms mean and why they matter, read on. (No, “free software” doesn’t just mean that you can download it for free.) Whether a program is open-source or not doesn’t just matter to developers, it ultimately matters for users, too. Open-source software licenses give users freedoms they would not otherwise have. Image Credit: Quinn Dombrowski on Flickr How To Use USB Drives With the Nexus 7 and Other Android Devices Why Does 64-Bit Windows Need a Separate “Program Files (x86)” Folder? Why Your Android Phone Isn’t Getting Operating System Updates and What You Can Do About It

  Read the article

• Need Help With Partioning

  - by Rakesh Kumar

  I bought a new laptop with no OS and decided to try to linux (Ubuntu) for the first time in my life. It was a clean install, my laptop had no other OS present in it, not even DOS. While installing, it asked for partitioning. Out of the 320GB of free space I created a new partition of 20 GB and installed Ubuntu in it. The rest of the 300GB is still available as free space. Soon I realized that I can't use the 300GB of space and that only 20GB is available to me for use. Can anyone tell me how I can take away some free space away from the 300GB and add that to my 20GB partition? I have installed the Gparted Partition editor from the Ubuntu Software Center but have no idea how to go ahead with it. Thanks :)

  Read the article

< Previous Page | 143 144 145 146 147 148 149 150 151 152 153 154  | Next Page >