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  • Learning WPF GUI design

    - by Jon
    GUI's written using WPF seem to be closer to a Web 2.0 feel than older Winforms development has been; do you know of any good quality references online or books which give a general overview of how to design nice WPF applications? I saw this StackOverflow question where some GUI design books are mentioned, but am interested in information specifically for WPF. http://stackoverflow.com/questions/1193001/is-wpf-silverlight-design-worth-learning Thanks!

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  • Non-Relational Database Design

    - by Ian Varley
    I'm interested in hearing about design strategies you have used with non-relational "nosql" databases - that is, the (mostly new) class of data stores that don't use traditional relational design or SQL (such as Hypertable, CouchDB, SimpleDB, Google App Engine datastore, Voldemort, Cassandra, SQL Data Services, etc.). They're also often referred to as "key/value stores", and at base they act like giant distributed persistent hash tables. Specifically, I want to learn about the differences in conceptual data design with these new databases. What's easier, what's harder, what can't be done at all? Have you come up with alternate designs that work much better in the non-relational world? Have you hit your head against anything that seems impossible? Have you bridged the gap with any design patterns, e.g. to translate from one to the other? Do you even do explicit data models at all now (e.g. in UML) or have you chucked them entirely in favor of semi-structured / document-oriented data blobs? Do you miss any of the major extra services that RDBMSes provide, like relational integrity, arbitrarily complex transaction support, triggers, etc? I come from a SQL relational DB background, so normalization is in my blood. That said, I get the advantages of non-relational databases for simplicity and scaling, and my gut tells me that there has to be a richer overlap of design capabilities. What have you done? FYI, there have been StackOverflow discussions on similar topics here: the next generation of databases changing schemas to work with Google App Engine choosing a document-oriented database

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  • Debugging MinGW program with gdb on Windows, not terminating at assert failure

    - by devil
    How do I set up gdb on window so that it does not allow a program with assertion failure to terminate? I intend to check the stack trace and variables in the program. For example, running this test.cpp program compiled with MinGW 'g++ -g test.cpp -o test' in gdb: #include <cassert> int main(int argc, char ** argv) { assert(1==2); return 0; } Gives: $ gdb test.exe GNU gdb 6.8 Copyright (C) 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "i686-pc-mingw32"... (gdb) r Starting program: f:\code/test.exe [New thread 4616.0x1200] Error: dll starting at 0x77030000 not found. Error: dll starting at 0x75f80000 not found. Error: dll starting at 0x77030000 not found. Error: dll starting at 0x76f30000 not found. Assertion failed: 1==2, file test.cpp, line 2 This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Program exited with code 03. (gdb) I would like to be able to stop the program from terminating immediately, like how Visual Studio's debugger and gdb on Linux does it. I have done a search and found some stuff on trapping signals but I can't seem to find a good post on how to set up gdb to do this.

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  • Design view disappeared from Interface Builder

    - by skywalker168
    All of a sudden, the visual design window disappeared from my Interface Builder. It is a regular UIView, has some UIImageView, UILabel, and UIButtons on it. When I open IB, I can see the document window (with File's Owner, First Responder and View in it), Library and Inspector, but the visual design window disappeared. Double click on "View" in the document window doesn't do anything. If I go to List mode, I can see all the components on the view, but just can no longer find the visual design window. All other XIB can open just fine, only this XIB lost its design window. First I thought maybe it was hidden somewhere on the screen. Tried all kinds of things, even rebooting the computer, but nothing helped. Can anyone help? Thanks in advance! By the way, I'm running SDK 3.2 Beta 3.

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  • Summation loop program in Pascal

    - by user2526598
    I am having a bit of an issue with this problem. I am taking a Pascal programming class and this problem was in my logic book. I am required to have the user enter a series of (+) numbers and once he/she enters a (-) number, the program should find the sum of all the (+) numbers. I accomplished this, but now I am attempting part two of this problem, which requires me to utilize a nested loop to run the program x amount of times based on the user's input. The following code is what I have so far and honestly I am stumped: program summation; //Define main program's variables var num, sum, numRun : integer; //Design procedure that will promt user for number of runs procedure numRunLoop ( var numRun : integer ); begin writeln('How many times shall I run this program?'); readln(numRun); end; //Design procedure that will sum a series of numbers //based on user input procedure numPromptLoop( numRun : integer; var num : integer ); var count : integer; begin //Utilize for to establish run limit for count := 1 to numRun do begin //Use repeat to prompt user for numbers repeat writeln('Enter a number: '); readln(num); //Tells program when to sum if num >= 0 then sum := sum + num; until num < 0; end; end; //Design procedure that will display procedure addItion( sum : integer ); begin writeln('The sum is; ', sum); end; begin numRunLoop(numRun); numPromptloop(numRun, num); addItion(sum); readln(); end.

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  • Decompiling an old Program

    - by Pedro Laranjeiro
    Hi. I have been asked to update a program written in 1987 in Delphi (I guess). I have no documentation about this program only a few side notes the programmer took that don't make too much sense to make. The cd show this files: Size | Filename - 19956 VP.DTA - 142300 VP.LEX - 404 VP.NDX - 126502 VP.RCS - 131016 VP.SCR - 150067 VP.XEL - 101791 vp.exe Is anyone of this files a database? If so can I access it's data? I tried several code decompilers but they show a message saying it was not a Win32 compatible application. The program run in MS-DOS. Is it possible to obtain the source code? Can I use this code in any way to build a new application? Thanks Update01: I can run the program in MSDOS. The program conjugate verbs and shows an example sentence where the verb can be used. The GUI is a little bit confusing and there is no help menu so I can't see all the capabilities of the program.

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  • How do you export or release a Mac OS X program made in Xcode? Program does not load on other comput

    - by SolidSnake4444
    I made a program in Xcode, being a simple calculator that takes a first number, and a second number, and then either adds,subtracts,multiplies, or divides depending on the radio button. I build and run and the program comes up and works fine. When I went to show my friends on their macs, when you double click on the program the program pops in the tray for like .05 seconds and then disappears and we never can actually run the program. It still works perfect however on my computer. What am I doing wrong? How can I take the program I made, and run it on different macs? I have the release set to 10.5 but the active SDK to 10.6. It runs in both 10.5 and 10.6 simulators. One friend has 10.6.3 like me and the other has 10.5.x(cant remember the last part). To get the app, I changed from debug to release and set active SDK to 10.5. Then in the release folder I found the app and sent that over iChat. I feel this will be a problem in the future if I ever make a legit application to distribute. Thank you!

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  • Database design question

    - by Lijo
    Hi Team, I have an interesting database design problem that I formulated while travelling by a bus, coming back from my home. Design a normalized database for a bus ticketing system (not reservation system). In each trip, the conductor of the bus will give tickets to its passengers after collecting fare from them. Passengers travel from a various source places to various destination places. The system must be able to give a report of the places for which the number of passengers was more than 2. Suppose the stops for the bus are L1,L2, L3 and L4 Suppose passenger P1 travels from L1 to L4. P2 travels from L2 to L4. P3 travels from L3 to L4. The report should list only (L3-L4) for which it has more than 2 travelers. Can you please help me to solve the following problems 1) Design a normalized database 2) Write a query for the report 3) Is there any site that gives these kinds of interesting database design questions and answers? Thanks Lijo

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  • Best Design for creating Historic Reports on GAE

    - by charming30
    My App requires Daily reports based on various user activities. My current design does not sum the daily totals in database, which means I must compute them everytime. For example A report that shows Top 100 users based on the number of submissions they have made on a given day. For such a report If I have 50,000 users, what is the best way to create daily report? How to create monthly and yearly report with such data? If this is not a good design, then how to deal with such design decision when the metrics of the report are not clear during db design and by the time it is clear we already have huge data with limited parameters (fields). Please advice.

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  • Ios development with design issues

    - by user3651999
    I don't know this question wether have been asked or not. But i research and found nothing.So my problem is i kinda new in IOS development. In android we can edit or customize design using UI and code(XML file). I prefer code.Does IOs have such file to edit/customize the design?Because I saw people always edit their design using the built-in UI rather than coding .I mean in design part not in function part.I would love using code any suggestion? Apperciate for any reply!

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  • Fitting it together, database, reporting, applications in C#

    - by alvonellos
    Introduction Preamble I was hesitant to post this, since it's an application whose intricate details are defined elsewhere, and answers may not be helpful to others. Within the past few weeks (I was actually going to write a blog post about this after I finished) I've discovered that the barrier I'm encountering is one that's actually quite common for newer developers. This question is not so much about a specific thing as it is about piecing those things together. I've searched the internet far and wide, and found many tutorials on how to create applications that are kind of similar to what I'm looking for. I've also looked at hiring another, more experienced, developer to help me along, but all I've gotten are unqualified candidates that don't have the experience necessary and won't take care of the client or project like I will. I'd rather have the project never transpire than to release a solution that is half-baked. I've asked professors at my school, but they've not turned up answers to my question. I'm an experienced developer, and I've written many applications that are -- very abstractly -- close to what I'm doing, but my experiences from those applications aren't giving me enough leverage to solve this particular problem. I just hope that posting this article isn't a mistake for me to write. Project Description I have a project I'm working on for a client that is a rewrite of an application, originally written in Foxpro 2.6 by someone before me, that performs some analysis (which, sadly, I'm not allowed to disclose as per of my employment contract) on financial data. One day, after a long talk between the client and I -- where he intimately described his frustrations with all the bugs I've been hacking out of this code for 6 months now -- he told me to just rewrite it and gave me a month to write a good 1/8 of this 65k LOC Foxpro monstrosity. this 65k line of code foxpro monstrosity. It'll take me a good 3 - 6 months to rewrite this software (I know things the original programmer did not, like inheritance) going as I am right now, but I'm quickly discovering that I'm going to need to use databases. Prior to this contract I didn't even know about foxpro, and so I've had to learn foxpro on the fly, write procedures and make modifications to the database. I've actually come to like it, and this project would be rewritten in Foxpro if it were still a supported language, because over the past few months, I've come to like the features of Foxpro that make it so easy to develop data-driven applications. I once perfomed an experiment, comparing C# to Foxpro. What took me 45 minutes in C# took me two in Foxpro, and I knew C# prior to Foxpro. I was hoping to leverage the power of C#, but it intimidates me that in foxpro, you can have one line of code and be using a database. Prior to this, I have never written any serious database development from scratch. All the applications that I've written are in a different league. They are either completely data-naive or data-naive enough that I can get away with not using a database through serialization or by designing algorithms that work with the data in a manner that is stateless, so there is no need to worry about databases. I've come to realize, very quickly, that serialization and my efficacy with data structures has been my crutch all these years that's prevented me from adventuring into databases, and has consequently hindered my success in real-world programming. Sure, I've written some database stuff in Perl and Python, and I've done forms and worked with relational databases and tables, I'm a wizard in Access and Excel (seriously) and can do just about anything, but it just feels unnatural writing SQL code in another language... I don't mind writing SQL, and I don't It's that bridge between the database and the program code that drives me absolutely bonkers. I hope I'm not the only one to think this, but it bothers me that I have to create statements like the following string sSql = "SELECT * from tablename" When there's really no reason for that kind of unchecked language binding between two languages and two API's. Don't get my wrong, SQL is great, but I don't like the idea that, when executing commands on a SQL database, that one must intermix database and application software, and there's no database independence, which means that different versions of different databases can break code. This isn't very nice. The nicest thing about Foxpro is the cohesiveness between programming language and database. It's so easy, and Foxpro makes it easy, because the tool just fits the task. I can see why so many developers have created a career with this language, because it lowered the barrier of entry to data-driven applications that so many businesses need. It was wonderful. For my purposes today, with the demands and need for community support, extensibility, and language features, Foxpro isn't a solution that I feel would be the right tool for the job. I'm also worried about working too heavy with the database, because I've seen data-driven .NET applications have issues with database caches, running out of memory, and objects in the database not being collected. (Memory leaks) And OH the queries. Which one, how, and why? There are a plethora of different ways that a database can be setup, I think I counted 5 or 6 different kinds of database applications alone that I can chose from. That is a great mountain for me to climb when I don't even know where to begin when it comes to writing data-driven applications. The problem isn't that I don't know SQL or that I don't know C#. I know both and have worked with both extensively. It's making them work together that's the problem, and it's something I've never done in C# before. Reports The client likes paper. The data needs to be printed out in a format that is extensible, layered, and easy to use. I have never done reporting before, and so this is a bit of a problem. From the data source comes crystal reports, and so there's a dependency on the database, from what I understand. Code reuse A large part of the design decision that I've gone through so far is to break the task of writing a piece of this software into routines and modular DLL's and so forth such that much of the code can be reused. For example, when I setup this database, I want to be able to reuse the same database code over and over again. I also want to make sure that when the day comes that another developer is here, that he/she will be able to pick up just where I left off. The quicker I develop these applications, the better off I am. Tasks & Goals In my project, I need to write routines that apply algorithms and look for predefined patterns in financial data. Additionally, I need to simulate trading based on predefined algorithms and data. Then I need to prepare reports on that data. Additionally, I need to have a way to change the code base for this application quickly and effectively, without hacking together some band-aid solution for a problem that really needs a trauma ward. Special Considerations The solution must be fast, run quickly on existing hardware, and not be too much of a pain to maintain and write. I understand that anything I write I'm married to -- I'm responsible for the things that I write because my reputation and livelihood is dependent on it. Do I really need a database? What about performance? Performance was such a big issue that I hand wrote a data structure that is capable of performing 2 billion operations, using a total of 4 gigs of memory in under 1/4 of a second using the standard core two duo processor. I could not find a similar, pre-written data structure in C# to perform this task. What setup do I use in terms of database? What about reporting? I'd prefer to have PDF's generated, but I'd like to be able to visually sketch those reports and then just have a ReportFactory of some sort, that when I pass some variables in, it just does that data. About Me I'm a lone developer for a small business in this area. This is the first time I've done this and I've never had the breadth and depth of my knowledge tested. I'm incredibly frustrated with this project because I feel incredibly overwhelmed with the task at hand. I'm looking for that entry level point where I can draw a line and say "this is what I need to do" Conclusion I may have not been clear enough on my post. I'm still new to this whole thing, and I've been doing my best to contribute back to the community that I've leached so much knowledge from. I'd be glad to edit my post and add more information if possible. I'm looking for a big-picture solution or design process that helps me get off the ground in this world of data-driven applications, because I have a feeling that it's going to be concentric to my entire career as a programmer for some time. Specifically, if you didn't get it from the rest of the post (I may not have been clear enough) I really need some guidance as to where to go in terms of the design decisions for this project. Some things that'll be useful will be a pro/con list for the different kinds of database projects available in VS2010. I've tried, but generating that list has been as hard as solving the problem itself... If you could walk a developer writing a data-driven application for the first time in C#, how would you do that? Where would you point them to?

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  • Failed to mount to nfs server with "Program not Registered"

    - by Farrel
    I'm trying to setup nfs server on Fedora 17 and I'm getting "Program not Registered" error when I'm trying to mount. I guess the main reason for this is rpcbind. I'm a newbie in linux, so I don't know what info should I provide you with. Here is some info that might be useful. rpcinfo -p program vers proto port service 100000 4 tcp 111 portmapper 100000 3 tcp 111 portmapper 100000 2 tcp 111 portmapper 100000 4 udp 111 portmapper 100000 3 udp 111 portmapper 100000 2 udp 111 portmapper 100005 1 udp 20048 mountd 100005 1 tcp 20048 mountd 100005 2 udp 20048 mountd 100005 2 tcp 20048 mountd 100005 3 udp 20048 mountd 100005 3 tcp 20048 mountd 100024 1 udp 42223 status 100024 1 tcp 50054 status cat /etc/exports /home/Farrel/prog 192.168.xxx.xxx (ro,sync) service nfs status Redirecting to /bin/systemctl status nfs.service nfs-server.service - NFS Server Loaded: loaded (/usr/lib/systemd/system/nfs-server.service; enabled) Active: active (exited) since Fri, 02 Nov 2012 09:29:04 +0300; 5min ago Process: 924 ExecStartPost=/usr/lib/nfs-utils/scripts/nfs-server.postconfig (code=exited, status=0/SUCCESS) Process: 909 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS ${RPCNFSDCOUNT} (code=exited, status=0/SUCCESS) Process: 885 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS) Process: 864 ExecStartPre=/usr/lib/nfs-utils/scripts/nfs-server.preconfig (code=exited, status=0/SUCCESS) CGroup: name=systemd:/system/nfs-server.service Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable. Firewall is disabled on both systems. I spent a lot of time reading on the topic but all manuals on setting up nfs server lead to "Program not Registered" error. Any how-to-fix-it ideas?

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  • how to properly set environment variables

    - by avorum
    I've recently started using Windows (having used Ubuntu up until now) and I find myself unable to properly set environment variables. Whenever I set them they don't seem to work. I've been going to Start-Edit Environment Variables for your Account and editing the PATH value in the upper half of the GUI. Here's what I've got so far. ;C:\Chocolatey\bin;C:\tools\mysql\current\bin;C:\Program Files (x86)\Git\bin;C:\Program Files\MySQL\MySQL Server 5.6\bin\;C:\Python33\Scripts; These are each the parent directories of the executables I'd like to be able to run by name from CMD, but mysql, git, and pip aren't being recognized. Am I doing something wrong syntactically or at a general understanding level? I'd like to be able to run these commands without having to specify the full path to the executables every time. EDIT: The full PATH extracted from CMD PATH=C:\Python33\;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;C:\Program Files (x86)\AMD APP\bin\x86_64;C:\Program Files (x86)\AMD APP\bin\x86;C:\Program Files\Common Files\Microsoft Shared\Windows Live;C:\Program Files (x86)\Common Files\Microsoft Shared\Windows Live;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\GTK2-Runtime\bin;C:\Program Files\WIDCOMM\Bluetooth Software\;C:\Program Files\WIDCOMM\Bluetooth Software\syswow64;C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static;C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\v1.0\;C:\Program Files\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files (x86)\QuickTime\QTSystem\;C:\Program Files (x86)\Common Files\Acronis\SnapAPI\;C:\Program Files (x86)\Java\jre7\bin;C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\;C:\Program Files (x86)\Microsoft SDKs\TypeScript\;C:\Program Files (x86)\MySQL\MySQL Utilities 1.3.4\; ;C:\Chocolatey\bin;C:\tools\mysql\current\bin I'm being forced to use Windows by my work environment, I don't enjoy the state of affairs.

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  • Program for remove exact duplicate files while caching search results

    - by John Thomas
    We need a Windows 7 program to remove/check the duplicates but our situation is somewhat different than the standard one for which there are enough programs. We have a fairly large static archive (collection) of photos spread on several disks. Let's call them Disk A..M. We have also some disks (let's call them Disk 1..9) which contain some duplicates which are to be found on disks A..M. We want to add to our collection new disks (N, O, P... aso.) which will contain the photos from disks 1..9 but, of course, we don't want to have any photos two (or more) times. Of course, theoretically, the task can be solved with a regular file duplicate remover but the time needed will be very big. Ideally, AFAIS now, the real solution would be a program which will scan the disks A..M, store the file sizes/hashes of the photos in an indexed database/file(s) and will check the new disks (1..9) against this database. However I have hard time to find such a program (if exists). Other things to note: we consider that the Disks A..M (the collection) doesn't have any duplicates on them the file names might be changed we aren't interested in approximated (fuzzy) comparison which can be found in some photo comparing programs. We hunt for exact duplicate files. we aren't afraid of command line. :-) we need to work on Win7/XP we prefer (of course) to be freeware TIA for any suggestions, John Th.

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  • Need help finding a program to split PDFs based on text in specific areas

    - by Sean
    I reeeeally need help with this. I work for a University in the admissions office and we get large PDFs of every document that an applicant uploads to us. What I need to do is split these PDFs into separate documents. Each of the separate documents has a head at the top of what type of document it is (Statement of Purpose, Transcript, etc). I found a program a few weeks ago that at first seemed to work great (A-PDF Splitter). It would look for every type of document in a combined PDF (eg. Statement of Purpose), and if it saw that heading it would create a new PDF named "ORIGINALFILENAME-Statement of Purpose". I soon discovered though that the program breaks for no reason on certain PDFs, and I have to take the time to take that PDF out of the queue and start the splitting over again (and we get 250 a day). I contacted their support and they basically told me I was SOL. So please, if you can find me a program to split PDFs into smaller PDFs based on if it finds particular text in a region, then I would be forever in dept to you. If I don't find one soon then I'm going to be spending the entire day splitting PDFs by hand and my boss isn't going to be happy.

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  • Tips to Make Your Website Cell Phone Friendly

    - by Aditi
    Working on a new website design? or Redesigning your website? There is a lot more to consider now a days not just user experience, clean code, CSS etc. one of the important attribute one must not miss, which is making them mobile friendly! With the growing use of handhelds & unlimited data plans, people browse on their cellphones! and All come in different sizes! it is tough to make a website that would look great not just on a high resolution widescreen monitor/LCD, but also should look equally impressive on the low resolutions of cellphones. We are today going to discuss about such factors that can help you make a website Cellphone Friendly. Fluid Width Layouts As we start discussing about this, Most people speak of the Fluid Width Layouts as vital step in moving your website to be mobile friendly. Fluid width allows the width of your website stretch or shrink depending on the browser size. However, having a layout which flows with the width of the screen’s resolution is certainly convenient, more often than not the website was originally laid out for a desktop in mind. Compressing a fluid layout to 320 pixels can do some serious damage to layout, Thus some people strongly believe it is far better to have a mobile style sheet and lay out the content specifically for that screen and have more control on the display. The best thing to do is to detect the type of platform that is connected to your website and disabling or changing some tools and effects to make it look better if not perfect. Keep Your Web Pages Short length One must avoid long pages on their website, a lot of scroll makes it very non user friendly for people, especially on mobile devices this is a huge draw back because of the longer load time it takes to download the webpage. Everyone likes crisp & concise content such pages are easier to load & browse. This makes your website accessible across all platforms. Also try to keep shorter urls, if they have to type..save them from that much work especially if someone is using a cellphone with no QWERTY keyboard it can be tough. Usable Navigation & Search Unlike Desktops, your website’s Navigation won’t super work on a cellphone. Keep in mind the user experience for cellphone users as you design your Navigation. Try to keep your content centered as they do have difficulty in reading the webpage. I always look upto Google and their pages as available on mobile as a great example. Keeping a functional & very visible search bar helps mobile users navigate by searching. Understanding Clean Website Code : Evolved for Mobile Clean code is important when you consider the diversity out there for handheld devices. Some cell phones may only understand WAP. More capable phones may understand WAP2, which allows rendering websites with XHTML and CSS. Most mobiles won’t display tables, floats, frames, JavaScript, and dynamic menus. Most cellphone will not support cookies. Devices at the high end of the mobile market such as BlackBerry, Palm, or the upcoming iPhone are highly capable and support nearly as much as a standard computer..but masses still do not have such phones. You can use specific emulators to test your website on mobile devices. Make sure your color combinations provide good contrast between foreground and background colors, particularly for devices with fewer color options.

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  • Project structure: where to put business logic

    - by Mister Smith
    First of all, I'm not asking where does business logic belong. This has been asked before and most answers I've read agree in that it belongs in the model: Where to put business logic in MVC design? How much business logic should be allowed to exist in the controller layer? How accurate is "Business logic should be in a service, not in a model"? Why put the business logic in the model? What happens when I have multiple types of storage? However people disagree in the way this logic should be distributed across classes. There seem to exist three major currents of thought: Fat model with business logic inside entity classes. Anemic model and business logic in "Service" classes. It depends. I find all of them problematic. The first option is what most Fowlerites stick to. The problem with a fat model is that sometimes a business logic funtion is not only related to a class, and instead uses a bunch of other classes. If, for example, we are developing a web store, there should be a function that calcs an order's total. We could think of putting this function inside the Order class, but what actually happens is that the logic needs to use different classes, not only data contained in the Order class, but also in the User class, the Session class, and maybe the Tax class, Country class, or Giftcard, Payment, etc. Some of these classes could be composed inside the Order class, but some others not. Sorry if the example is not very good, but I hope you understand what I mean. Putting such a function inside the Order class would break the single responsibility principle, adding unnecesary dependences. The business logic would be scattered across entity classes, making it hard to find. The second option is the one I usually follow, but after many projects I'm still in doubt about how to name the class or classes holding the business logic. In my company we usually develop apps with offline capabilities. The user is able to perform entire transactions offline, so all validation and business rules should be implemented in the client, and then there's usually a background thread that syncs with the server. So we usually have the following classes/packages in every project: Data model (DTOs) Data Access Layer (Persistence) Web Services layer (Usually one class per WS, and one method per WS method). Now for the business logic, what is the standard approach? A single class holding all the logic? Multiple classes? (if so, what criteria is used to distribute the logic across them?). And how should we name them? FooManager? FooService? (I know the last one is common, but in our case it is bad naming because the WS layer usually has classes named FooWebService). The third option is probably the right one, but it is also devoid of any useful info. To sum up: I don't like the first approach, but I accept that I might have been unable to fully understand the Zen of it. So if you advocate for fat models as the only and universal solution you are welcome to post links explaining how to do it the right way. I'd like to know what is the standard design and naming conventions for the second approach in OO languages. Class names and package structure, in particular. It would also be helpful too if you could include links to Open Source projects showing how it is done. Thanks in advance.

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  • Making A C++ Game

    - by user1758938
    I'm gonna make a game and I think C++ would be perfect for it. I think I'm gonna use SDL and OpenGL but I need help with making the code manageable. These were my ideas: 1. Making A DLL File With Commands Such A CreateScreen(640, 480); Which Binds SDL And OpenGL Commands For A Manageable Setup 2. Making It Harder To Mod (Like UnCompiling My Code) Like Encrypting Save Files That Only My Program Can Read Any Suggestions?

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  • Embedded Web Server Vs External Web Server

    - by Jetti
    So I've thought of creating a web application in either Lisp or another functional language and was thinking of embedding the web server into the application (have my application handle the HTTP requests). I don't see any issues with that, however, I'm new to creating web applications (and in the grand scheme of things, programming as well). Is there any drawbacks to handling HTTP requests within your program instead of using a web server? Are there any benefits?

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  • Using virtual functions

    - by Tucker Morgan
    I am starting to use virtual functions, and i am programming a simple text game, my question is this, if i have a virtual function called spec_abil with in a Super class called rpg_class. If you allow the player to class what class they want to play, say a mage class, a archer class, and a warrior class, which all have their own spec_abil function. How do you write it so that the program knows which one to use depending on the chosen class.

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  • Developing a Cost Model for Cloud Applications

    - by BuckWoody
    Note - please pay attention to the date of this post. As much as I attempt to make the information below accurate, the nature of distributed computing means that components, units and pricing will change over time. The definitive costs for Microsoft Windows Azure and SQL Azure are located here, and are more accurate than anything you will see in this post: http://www.microsoft.com/windowsazure/offers/  When writing software that is run on a Platform-as-a-Service (PaaS) offering like Windows Azure / SQL Azure, one of the questions you must answer is how much the system will cost. I will not discuss the comparisons between on-premise costs (which are nigh impossible to calculate accurately) versus cloud costs, but instead focus on creating a general model for estimating costs for a given application. You should be aware that there are (at this writing) two billing mechanisms for Windows and SQL Azure: “Pay-as-you-go” or consumption, and “Subscription” or commitment. Conceptually, you can consider the former a pay-as-you-go cell phone plan, where you pay by the unit used (at a slightly higher rate) and the latter as a standard cell phone plan where you commit to a contract and thus pay lower rates. In this post I’ll stick with the pay-as-you-go mechanism for simplicity, which should be the maximum cost you would pay. From there you may be able to get a lower cost if you use the other mechanism. In any case, the model you create should hold. Developing a good cost model is essential. As a developer or architect, you’ll most certainly be asked how much something will cost, and you need to have a reliable way to estimate that. Businesses and Organizations have been used to paying for servers, software licenses, and other infrastructure as an up-front cost, and power, people to the systems and so on as an ongoing (and sometimes not factored) cost. When presented with a new paradigm like distributed computing, they may not understand the true cost/value proposition, and that’s where the architect and developer can guide the conversation to make a choice based on features of the application versus the true costs. The two big buckets of use-types for these applications are customer-based and steady-state. In the customer-based use type, each successful use of the program results in a sale or income for your organization. Perhaps you’ve written an application that provides the spot-price of foo, and your customer pays for the use of that application. In that case, once you’ve estimated your cost for a successful traversal of the application, you can build that into the price you charge the user. It’s a standard restaurant model, where the price of the meal is determined by the cost of making it, plus any profit you can make. In the second use-type, the application will be used by a more-or-less constant number of processes or users and no direct revenue is attached to the system. A typical example is a customer-tracking system used by the employees within your company. In this case, the cost model is often created “in reverse” - meaning that you pilot the application, monitor the use (and costs) and that cost is held steady. This is where the comparison with an on-premise system becomes necessary, even though it is more difficult to estimate those on-premise true costs. For instance, do you know exactly how much cost the air conditioning is because you have a team of system administrators? This may sound trivial, but that, along with the insurance for the building, the wiring, and every other part of the system is in fact a cost to the business. There are three primary methods that I’ve been successful with in estimating the cost. None are perfect, all are demand-driven. The general process is to lay out a matrix of: components units cost per unit and then multiply that times the usage of the system, based on which components you use in the program. That sounds a bit simplistic, but using those metrics in a calculation becomes more detailed. In all of the methods that follow, you need to know your application. The components for a PaaS include computing instances, storage, transactions, bandwidth and in the case of SQL Azure, database size. In most cases, architects start with the first model and progress through the other methods to gain accuracy. Simple Estimation The simplest way to calculate costs is to architect the application (even UML or on-paper, no coding involved) and then estimate which of the components you’ll use, and how much of each will be used. Microsoft provides two tools to do this - one is a simple slider-application located here: http://www.microsoft.com/windowsazure/pricing-calculator/  The other is a tool you download to create an “Return on Investment” (ROI) spreadsheet, which has the advantage of leading you through various questions to estimate what you plan to use, located here: https://roianalyst.alinean.com/msft/AutoLogin.do?d=176318219048082115  You can also just create a spreadsheet yourself with a structure like this: Program Element Azure Component Unit of Measure Cost Per Unit Estimated Use of Component Total Cost Per Component Cumulative Cost               Of course, the consideration with this model is that it is difficult to predict a system that is not running or hasn’t even been developed. Which brings us to the next model type. Measure and Project A more accurate model is to actually write the code for the application, using the Software Development Kit (SDK) which can run entirely disconnected from Azure. The code should be instrumented to estimate the use of the application components, logging to a local file on the development system. A series of unit and integration tests should be run, which will create load on the test system. You can use standard development concepts to track this usage, and even use Windows Performance Monitor counters. The best place to start with this method is to use the Windows Azure Diagnostics subsystem in your code, which you can read more about here: http://blogs.msdn.com/b/sumitm/archive/2009/11/18/introducing-windows-azure-diagnostics.aspx This set of API’s greatly simplifies tracking the application, and in fact you can use this information for more than just a cost model. After you have the tracking logs, you can plug the numbers into ay of the tools above, which should give a representative cost or in some cases a unit cost. The consideration with this model is that the SDK fabric is not a one-to-one comparison with performance on the actual Windows Azure fabric. Those differences are usually smaller, but they do need to be considered. Also, you may not be able to accurately predict the load on the system, which might lead to an architectural change, which changes the model. This leads us to the next, most accurate method for a cost model. Sample and Estimate Using standard statistical and other predictive math, once the application is deployed you will get a bill each month from Microsoft for your Azure usage. The bill is quite detailed, and you can export the data from it to do analysis, and using methods like regression and so on project out into the future what the costs will be. I normally advise that the architect also extrapolate a unit cost from those metrics as well. This is the information that should be reported back to the executives that pay the bills: the past cost, future projected costs, and unit cost “per click” or “per transaction”, as your case warrants. The challenge here is in the model itself - statistical methods are not foolproof, and the larger the sample (in this case I recommend the entire population, not a smaller sample) is key. References and Tools Articles: http://blogs.msdn.com/b/patrick_butler_monterde/archive/2010/02/10/windows-azure-billing-overview.aspx http://technet.microsoft.com/en-us/magazine/gg213848.aspx http://blog.codingoutloud.com/2011/06/05/azure-faq-how-much-will-it-cost-me-to-run-my-application-on-windows-azure/ http://blogs.msdn.com/b/johnalioto/archive/2010/08/25/10054193.aspx http://geekswithblogs.net/iupdateable/archive/2010/02/08/qampa-how-can-i-calculate-the-tco-and-roi-when.aspx   Other Tools: http://cloud-assessment.com/ http://communities.quest.com/community/cloud_tools

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