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  • How to switch data pins on/off on parallel port?

    - by Matt
    I want to simply switch certain data pins on and off, so that they can control a set of relays. I'm not asking about the hardware bit (should be easy), but I don't know where to begin writing the software. I don't want a high level library that can send bytes to a device - I literally want to switch on/off certain pins. I'm running Linux and I want to do this in Java, so would I just need a library? It would be nice if the library has good documentation and is easy to use, but if not then a short example code will help me get started.

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  • free( ) pointers

    - by user1043625
    I'm required to use a special library to keep track of my memory leaks where malloc()= allocate( ) and free( ) = unallocate( ). I'm trying to complete free a linked-list but it seems like the "root" value isn't being freed. typedef struct _node { struct _node *child; char *command; } Command_list; void delete_commands(Command_list **root) { Command_list *temp; while( *root != NULL ){ temp = (*root)->child; //printf("STRING: %s\n", *root->command ); unallocate( *root ); *root = temp; } } The function that's calling it void file_processing( .... ){ Command_list *root = allocate(sizeof (Command_list)); root = NULL; .... delete_commands( &root ); } } I believe that Command_list *root = allocate(sizeof (Command_list)) isn't being properly de-allocated for some reason. Anyone can give me some hints? UPDATE: I found out that instead of Command_list *root = allocate(sizeof (Command_list)); root = NULL; this works: Command_list *root = NULL;

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  • Silverlight "Out of browser application" vs. "Install from page"

    - by Matt McMinn
    I’ve been working on integrating some controls which call in to COM classes in to a Silverlight client. Since my controls use COM, they only work out of browser. The client does have out of browser installation options turned on, and when I launch the client from visual studio, I can right click it, and install it to the desktop. That all seems to be working fine. The strange part though is that my controls don’t work when they’re out of browser – I get an error that the COM server can’t be started. The stranger part is that if I go in to the clientproperties, and set the Start Action from “Dynamically generate a test page” to “Out of browser application”, my controls work fine, and I get no COM errors. So I guess I don’t understand the difference between installing the application to the desktop through the right click menu and setting the application to start as an out of browser application. Any idea what's going on here?

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  • RoR: Condition Always False - Why?

    - by Matt Hollingsworth
    Working in RoR 2.3.x. My quiz_results table has a row for user_id (3907) and result (0.1), and two users I'm looking at with no rows in the quiz_results table. This line keeps returining false: -if QuizResult.find_by_user_id(@user_id).present? But if I change it to anything that returns true, the next line reports an error on the * method: ="#{(QuizResult.average('score', :conditions => 'user_id = #{@user.id}') * 100).round}%" The beginning of the code is a loop: [email protected] do |user| Any ideas how to fix? Have tried unsuccessfully all day.

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  • Without LIB And String file how can i write this code??

    - by muhammadlodhi
    #include<stdio.h> #include<conio.h> #include<stdlib.h> #include<string.h> struct Node; typedef struct Node * PtrToNode; struct Node { char element; PtrToNode Next; }; PtrToNode MakeEmpty(PtrToNode L) { L= new(Node); L->Next=NULL; return L; } void Push(PtrToNode L,char x) { PtrToNode S; S= new(Node); S->element=x; S->Next=L->Next; L->Next=S; } char Pop(PtrToNode L) { PtrToNode P; P=L->Next; char x=P->element; L->Next=P->Next; free(P); return x; } int main() { PtrToNode L; L= MakeEmpty(NULL); char Input[1000]; int i; printf("please enter your equation:"); scanf("%s",Input); for (i = 0;i<strlen(Input);i++) { if (Input[i]=='(') { Push(L,Input[i]); } if (Input[i]==')') { if (L->Next==NULL) { printf("incorrect"); return 0; } else Pop(L); } } if (L->Next==NULL) printf("correct"); else printf("incorrect"); getch(); return 0; }

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  • Is there a way in VS2008 (c#) to see all the possible exception types that can originate from a meth

    - by Matt
    Is there a way in VS2008 IDE for c# to see all the possible exception types that can possibly originate from a method call or even for an entire try-catch block? I know that intellisense or the object browser tells me this method can throw these types of exceptions but is there another way than using the object browser everytime? Something more accessible when coding? Furthermore, I don't think intellisense or the object browser do anything more than read the XML code comments. Shouldn't it be possible to scan a class's source and find all the exception types that can be thrown. (Forget path-ing based on method input, just scan the code for exception types) Am I wrong? Extending this idea, you should be able to hover over the 'try' or 'catch' keywords and present a tooltip with all the types of exceptions that can be thrown. My question boils down to, does a VS2008 add on like this exist? Does VS2010 do this perhaps? If not, could you implement it the way I've described, by scanning the class code for thrown exception types and would people find it useful. Exceptions bubble up so you have to scan every bit of code every method call, which I guess could be impractical, though I suppose you could build an index the first time and increase your speed that way. (It might be a cool little project....)

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  • Is this Leftist Tree piece of code from Wikipedia correct?

    - by they changed my name
    Link public Node merge(Node x, Node y) { if(x == null) return y; if(y == null) return x; // if this was a max height biased leftist tree, then the // next line would be: if(x.element < y.element) if(x.element.compareTo(y.element) > 0) { // x.element > y.element Node temp = x; x = y; y = temp; } x.rightChild = merge(x.rightChild, y); if(x.leftChild == null) { // left child doesn't exist, so move right child to the left side x.leftChild = x.rightChild; x.rightChild = null; x.s = 1; } else { // left child does exist, so compare s-values if(x.leftChild.s < x.rightChild.s) { Node temp = x.leftChild; x.leftChild = x.rightChild; x.rightChild = temp; } // since we know the right child has the lower s-value, we can just // add one to its s-value x.s = x.rightChild.s + 1; } return x; } What makes me ask this question is: if(x.element.compareTo(y.element) > 0) { // x.element > y.element Node temp = x; x = y; y = temp; } Isn't that just not gonna work, since the references are only switched inside the method?

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  • Make qwidget in new window in PyQt4

    - by matt
    I'm trying to make a class that extends qwidget, that pops up a new window, I must be missing something fundamental, class NewQuery(QtGui.QWidget): def __init__(self, parent): QtGui.QMainWindow.__init__(self,parent) self.setWindowTitle('Add New Query') grid = QtGui.QGridLayout() label = QtGui.QLabel('blah') grid.addWidget(label,0,0) self.setLayout(grid) self.resize(300,200) when a new instance of this is made in main window's class, and show() called, the content is overlaid on the main window, how can I make it display in a new window?

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  • Trying to use a list iterator to print out entire linked list in Java. Infinite loop for some reaso

    - by Matt
    I created my list: private static List list = new LinkedList(); and my iterator: ListIterator itr = list.listIterator(); and use this code to try to print out the list... Only problem is, it never comes out of the loop. When it reaches the tail, shouldn't it come out of the loop, because there is no next? Or is it going back to the head like a circular linked list? It is printing so quickly and my computer locks up shortly after, so I can't really tell what is going on. while (itr.hasNext()) System.out.println(itr.next());

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  • C# lines of Code

    - by matt
    What does this do exactly? var counts = new Dictionary<string, int>(); for (int i = 0; i < 10; i++) counts[string.Format("STA Thread Queue Worker Thread No. {0}", i + 1)] = 0; Thanks

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  • How do you create domain.com/?stringhere without a .php extention

    - by matt
    I want to create a link like the following: http://www.myurl.com/?IDHERE What i want to be able to do is be able to goto the above link, and then pull whats after the ? (in this case IDHERE) and be able to use that information to perform a MySQL lookup and return a page. Can anyone point me into the right direction? please know this is using PHP not ASP

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  • Is this a bad indexing strategy for a table?

    - by llamaoo7
    The table in question is part of a database that a vendor's software uses on our network. The table contains metadata about files. The schema of the table is as follows Metadata ResultID (PK, int, not null) MappedFieldname (char(50), not null) Fieldname (PK, char(50), not null) Fieldvalue (text, null) There is a clustered index on ResultID and Fieldname. This table typically contains millions of rows (in one case, it contains 500 million). The table is populated by 24 workers running 4 threads each when data is being "processed". This results in many non-sequential inserts. Later after processing, more data is inserted into this table by some of our in-house software. The fragmentation for a given table is at least 50%. In the case of the largest table, it is at 90%. We do not have a DBA. I am aware we desperately need a DB maintenance strategy. As far as my background, I'm a college student working part time at this company. My question is this, is a clustered index the best way to go about this? Should another index be considered? Are there any good references for this type and similar ad-hoc DBA tasks?

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  • Within SSIS - Is it possible to deploy one package multiple times in the same instance and set diffe

    - by Matt
    In my environment my Dev and QA Database Instances are on the same server. I would like to deploy the same package (or different versions of the package) into SSIS and set the filter to select different rows in the Config table. Is this possible? This is SQL 2005. For the sake of this question lets say I have one variable, which is a directory path. I would like to have these variables in the table twice (with different Filters applied (Dev and QA) as below (simplified) . . . Filter / Variable Value / Variable Name Dev / c:\data\dev / FilePath QA / c:\data\qa / FilePath Do I need to apply a change within the settings of the package in SSIS or is it changed on the job step within Agent? Any help would be appreciated.

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  • Problem with passing array of pointers to struct among functions in C

    - by karatemonkey
    The Code that follows segfaults on the call to strncpy and I can't see what I am doing wrong. I need another set of eyes to look it this. Essentially I am trying to alloc memory for a struct that is pointed to by an element in a array of pointers to struct. #include <stdio.h> #include <stdlib.h> #include <string.h> #define MAX_POLICY_NAME_SIZE 64 #define POLICY_FILES_TO_BE_PROCESSED "SPFPolicyFilesReceivedOffline\0" typedef struct TarPolicyPair { int AppearanceTime; char *IndividualFile; char *FullPolicyFile; } PolicyPair; enum { bwlist = 0, fzacts, atksig, rules, MaxNumberFileTypes }; void SPFCreateIndividualPolicyListing(PolicyPair *IndividualPolicyPairtoCreate ) { IndividualPolicyPairtoCreate = (PolicyPair *) malloc(sizeof(PolicyPair)); IndividualPolicyPairtoCreate->IndividualFile = (char *)malloc((MAX_POLICY_NAME_SIZE * sizeof(char))); IndividualPolicyPairtoCreate->FullPolicyFile = (char *)malloc((MAX_POLICY_NAME_SIZE * sizeof(char))); IndividualPolicyPairtoCreate->AppearanceTime = 0; memset(IndividualPolicyPairtoCreate->IndividualFile, '\0', (MAX_POLICY_NAME_SIZE * sizeof(char))); memset(IndividualPolicyPairtoCreate->FullPolicyFile, '\0', (MAX_POLICY_NAME_SIZE * sizeof(char))); } void SPFCreateFullPolicyListing(SPFPolicyPair **CurrentPolicyPair, char *PolicyName, char *PolicyRename) { int i; for(i = 0; i < MaxNumberFileTypes; i++) { CreateIndividualPolicyListing((CurrentPolicyPair[i])); // segfaults on this call strncpy((*CurrentPolicyPair)[i].IndividualFile, POLICY_FILES_TO_BE_PROCESSED, (SPF_POLICY_NAME_SIZE * sizeof(char))); } } int main() { SPFPolicyPair *CurrentPolicyPair[MaxNumberFileTypes] = {NULL, NULL, NULL, NULL}; int i; CreateFullPolicyListing(&CurrentPolicyPair, POLICY_FILES_TO_BE_PROCESSED, POLICY_FILES_TO_BE_PROCESSED); return 0; }

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  • WPF Style Triggers: can I apply the one style for a variety of Properties?

    - by Matt H.
    It seems like there has to be a way to do this: I am applying an ItemContainerStyle in my Listbox, based on two property triggers. As you can see, I'm using the exact same set of trigger enter/exit actions, simply applied on two different properties. Is there something equivalent to a <Trigger Property="prop1" OR Property="prop2" ??? (Obviously wouldn't look like that, but that probably gets the point across.) <Style x:Key="ListBoxItemStyle" TargetType="ListBoxItem"> <Style.Triggers> <Trigger Property="IsKeyboardFocusWithin" Value="True"> <Trigger.EnterActions> <BeginStoryboard> <Storyboard> <DoubleAnimation Storyboard.TargetProperty="Height" To="50" Duration="0:0:.3"></DoubleAnimation> </Storyboard> </BeginStoryboard> </Trigger.EnterActions> <Trigger.ExitActions> <BeginStoryboard> <Storyboard> <DoubleAnimation Storyboard.TargetProperty="Height" To="25" Duration="0:0:.3" /> </Storyboard> </BeginStoryboard> </Trigger.ExitActions> </Trigger> </Style.Triggers> </Style> <Style x:Key="ListBoxItemStyle" TargetType="ListBoxItem"> <Style.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Trigger.EnterActions> <BeginStoryboard> <Storyboard> <DoubleAnimation Storyboard.TargetProperty="Height" To="50" Duration="0:0:.3"></DoubleAnimation> </Storyboard> </BeginStoryboard> </Trigger.EnterActions> <Trigger.ExitActions> <BeginStoryboard> <Storyboard> <DoubleAnimation Storyboard.TargetProperty="Height" To="25" Duration="0:0:.3" /> </Storyboard> </BeginStoryboard> </Trigger.ExitActions> </Trigger> </Style.Triggers> </Style>

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  • Credit card validation with regexp using test()

    - by Matt
    I'm trying to complete some homework and it appears the book might have gotten it wrong. I have a simple html page that allows user to pick a credit card in our case american express. The user then enters a number and evalutes that number based on a regular expression. My question ends up being when test() evaluates the number it returns a boolean or a string? I should then compare that string or boolean? True == true should fire off the code in a nested if statement. Heres what the book gives me as valid code: if(document.forms[0].cardName.value == "American Express") { var cardProtocol = new RegExp("^3[47][0-9]{13}$"); //REGEX ENTRY HERE if(cardProtocol.test(document.forms[0].cardNumber.value)) document.forms[0].ccResult.value = "Valid credit card number"; } The above code doesn't work in firefox. I've tried modifying it with 2 alerts to make sure the number is good and the boolean is good...and still no luck: if(document.forms[0].cardName.value == "American Express") { var cardProtocol = new RegExp("^3[47][0-9]{13}$"); //REGEX ENTRY HERE <------ alert(document.forms[0].cardNumber.value) alert(cardProtocol.test(document.forms[0].cardNumber.value)) if((cardProtocol.test(document.forms[0].cardNumber.value)) == true ) // <--Problem { document.forms[0].ccResult.value = "Valid credit card number"; } else { document.forms[0].ccResult.value = "Invalid credit card number"; } } Any ideas? the if loop is the culprit but I'm not figuring out why it is not working. Please throw up the code for the if loop! Thanks for the help!

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  • Nullable values in C++

    - by DanDan
    I'm creating a database access layer in native C++, and I'm looking at ways to support NULL values. Here is what I have so far: class CNullValue { public: static CNullValue Null() { static CNullValue nv; return nv; } }; template<class T> class CNullableT { public: CNullableT(CNullValue &v) : m_Value(T()), m_IsNull(true) { } CNullableT(T value) : m_Value(value), m_IsNull(false) { } bool IsNull() { return m_IsNull; } T GetValue() { return m_Value; } private: T m_Value; bool m_IsNull; }; This is how I'll have to define functions: void StoredProc(int i, CNullableT<int> j) { ...connect to database ...if j.IsNull pass null to database etc } And I call it like this: sp.StoredProc(1, 2); or sp.StoredProc(3, CNullValue::Null()); I was just wondering if there was a better way than this. In particular I don't like the singleton-like object of CNullValue with the statics. I'd prefer to just do sp.StoredProc(3, CNullValue); or something similar. How do others solve this problem?

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  • NSTableView not refreshing when calling method from different class

    - by Matt S.
    I have a table view that gets refreshed two different ways. One is through a button and the other is when I call my refresh method, which is the same method that I use for the button, but for some reason, when I hit the button it works, but when I call it through a different class it doesn't. Here's the code that I use to refresh the tableview: Msqv *qv = [Msqv new]; [qv refresh:self]; //refresh is an IBAction that is used by the button

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  • CSS 3 columns, why is the third column taking over the other 2?

    - by Matt Dawdy
    Here is the smallest amount of code that clearly illustrates my problem: <html> <body> <div style="float: left; width: 200px;">One</div> <div style="float: left; width: 200px;">Two</div> <div style="background-color: #f0f;">Three</div> </body> </html> The first 2 divs are supposed to be 2 left columns. The 3rd should take up the rest of the page. Eventually, I'm going to add options to hide and show the 2 columns on the left. But, why is the color purple extending all the way to the browser's left edge? I am trying to get it to start at the word "Three".

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  • Calling a constructor to reinitialize variables doesn't seem to work?

    - by Matt
    I wanted to run 1,000 iterations of a program, so set a counter for 1000 in main. I needed to reinitialize various variables after each iteration, and since the class constructor had all the initializations already written out - I decided to call that after each iteration, with the result of each iteration being stored in a variable in main. However, when I called the constructor, it had no effect...it took me a while to figure out - but it didn't reinitialize anything! I created a function exactly like the constructor - so the object would have its own version. When I called that, it reinitialized everything as I expected. int main() { Class MyClass() int counter = 0; while ( counter < 1000 ) { stuff happens } Class(); // This is how I tried to call the constructor initially. // After doing some reading here, I tried: // Class::Class(); // - but that didn't work either /* Later I used... MyClass.function_like_my_constructor; // this worked perfectly */ } ...Could someone try to explain why what I did was wrong, or didn't work, or was silly or what have you? I mean - mentally, I just figured - crap, I can call this constructor and have all this stuff reinitialized. Are constructors (ideally) ONLY called when an object is created?

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  • Assigning values from list to list excluding nulls

    - by GutierrezDev
    Hi. Sorry for the title but I don't know other way of asking. I got 2 Dictionary < string,string list One of them has a length of 606 items including null values. The other one has a length of 285 items. I determined the length doing this: int count = 0; for (int i = 0; i < temp.Length; i++) { if (temp[i] != null) count++; } Now I want to assign every value in the temp variable to another variable excluding the null values. Any Idea? Remember that I have a different size variables. Edited Dictionary<string, string>[] info; Dictionary<string, string>[] temp = new Dictionary<string, string>[ds.Tables[0].Rows.Count]; .... Here I added some data to the Temp variable ..... Then this: int count = 0 for (int i = 0; i < temp.Length; i++) { if (temp[i] != null) count++; } info = new Dictionary<string, string>[count]; Hope you understand now.

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