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• Efficient way to get highly correlated pairs from large data set in Python or R

  - by Akavall

  I have a large data set (Let's say 10,000 variables with about 1000 elements each), we can think of it as 2D list, something like: [[variable_1], [variable_2], ............ [variable_n] ] I want to extract highly correlated variable pairs from that data. I want "highly correlated" to be a parameter that I can choose. I don't need all pairs to be extracted, and I don't necessarily want the most correlated pairs. As long as there is an efficient method that gets me highly correlated pairs I am happy. Also, it would be nice if a variable does not show up in more than one pair. Although this might not be crucial. Of course, there is a brute force way to finding such pairs, but it is too slow for me. I've googled around for a bit and found some theoretical work on this issue, but I wasn't able for find a package that could do what I am looking for. I mostly work in python, so a package in python would be most helpful, but if there exists a package in R that does what I am looking for it will be great. Does anyone know of a package that does the above in Python or R? Or any other ideas? Thank You in Advance

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• refactoring my code. My headers (Header Guard Issues)

  - by numerical25

  I had a post similar to this awhile ago based on a error I was getting. I was able to fix it but since then I been having trouble doing things because headers keep blocking other headers from using code. Honestly, these headers are confusing me and if anyone has any resources that will address these types of issues, that will be helpful. What I essentially want to do is be able to have rModel.h be included inside RenderEngine.h. every time I add rModel.h to RenderEngine.h, rModel.h is no longer able to use RenderEngine.h. (rModel.h has a #include of RenderEngine.h as well). So in a nutshell, RenderEngine and rModel need to use each others functionalities. On top of all this confusion, the Main.cpp needs to use RenderEngine. stdafx.h #include "targetver.h" #define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers // Windows Header Files: #include <windows.h> // C RunTime Header Files #include <stdlib.h> #include <malloc.h> #include <memory.h> #include <tchar.h> #include "resource.h" main.cpp #include "stdafx.h" #include "RenderEngine.h" #include "rModel.h" // Global Variables: RenderEngine go; rModel *g_pModel; ...code........... rModel.h #ifndef _MODEL_H #define _MODEL_H #include "stdafx.h" #include <vector> #include <string> #include "rTri.h" #include "RenderEngine.h" ........Code RenderEngine.h #pragma once #include "stdafx.h" #include "d3d10.h" #include "d3dx10.h" #include "dinput.h" #include "rModel.h" .......Code......

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• batch: replace a line in a text file

  - by sasamimasas

  I'm trying to replace this line: # forward-socks5 / 127.0.0.1:9050 . with this one: forward-socks5 / 127.0.0.1:9050 . this line belongs to a config file that has to be enabled (UN-commented) by deleting the # sign from the beginning and I could not thought of a better way other than replacing the line with another without the # sign. any other thoughts or ways would be very useful. btw, the spaces before the text are there also.I have pasted the text as it was in the original file. thanks in advance EDIT: I have somehow managed to do the line addition and removing using two peaces of code that I've found. my only problem is that the following code removes every bit of exclamation in the output file! @echo off :Variables SETLOCAL ENABLEDELAYEDEXPANSION set InputFile=config.txt set OutputFile=config-new.txt set _strFind=# forward-socks5 / 127.0.0.1:9050 . set _strInsert= forward-socks5 / 127.0.0.1:9050 . set i=0 :Replace for /f "usebackq tokens=1 delims=[]" %%A in (`find /n "%_strFind%" "%InputFile%"`) do (set _strNum=%%A) for /f "usebackq delims=" %%A in ("%InputFile%") do ( set /a i = !i! + 1 echo %%A>>"%OutputFile%" if [!i!] == [%_strNum%] (echo %_strInsert%>>"%OutputFile%") ) type %OutputFile% | findstr /i /v /c:"%_strFind%">config-new2.txt I was wondering if there is any way to do both the find/delete/add line in one step (not two steps as mine)...

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• Write-Only Reference in C++?

  - by Robert Mason

  Is there a way to code a write-only reference to an object? For example, suppose there was a mutex class: template <class T> class mutex { protected: T _data; public: mutex(); void lock(); //locks the mutex void unlock(); //unlocks the mutex T& data(); //returns a reference to the data, or throws an exception if lock is unowned }; Is there a way to guarantee that one couldn't do this: mutex<type> foo; T& ref; foo.lock(); ref = foo.data(); foo.unlock(); //I have a unguarded reference to foo now On the other hand, is it even worth it? I know that some people assume that programmers won't deliberately clobber the system, but then, why do we have private variables in the first place, eh? It'd be nice to just say it's "Undefined Behavior", but that just seems a little bit too insecure.

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• C++ - Distributing different headers than development

  - by Ben

  I was curious about doing this in C++: Lets say I have a small library that I distribute to my users. I give my clients both the binary and the associated header files that they need. For example, lets assume the following header is used in development: #include <string> ClassA { public: bool setString(const std::string & str); private: std::string str; }; Now for my question. For deployment, is there anything fundamentally wrong with me giving a 'reduced' header to my clients? For example, could I strip off the private section and simply give them this: #include <string> ClassA { public: bool setString(const std::string & str); }; My gut instinct says "yes, this is possible, but there are gotchas", so that is why I am asking this question here. If this is possible and also safe, it looks like a great way to hide private variables, and thus even avoid forward declaration in some cases. I am aware that the symbols will still be there in the binary itself, and that this is just a visibility thing at the source code level. Thanks!

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• Mathmatic errors in basic C++ program

  - by Heather

  I am working with a basic C++ program to determine the area and perimeter of a rectangle. My program works fine for whole numbers but falls apart when I use any number with a decimal. I get the impression that I am leaving something out, but since I'm a complete beginner, I have no idea what. Below is the source: #include <iostream> using namespace std; int main() { // Declared variables int length; // declares variable for length int width; // declares variable for width int area; // declares variable for area int perimeter; // declares variable for perimeter // Statements cout << "Enter the length and the width of the rectangle: "; // states what information to enter cin >> length >> width; // user input of length and width cout << endl; // closes the input area = length * width; // calculates area of rectangle perimeter = 2 * (length + width); //calculates perimeter of rectangle cout << "The area of the rectangle = " << area << " square units." <<endl; // displays the calculation of the area cout << "The perimeter of the rectangle = " << perimeter << " units." << endl; // displays the calculation of the perimeter system ("pause"); // REMOVE BEFORE RELEASE - testing purposes only return 0; }

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• Does the Java Memory Model (JSR-133) imply that entering a monitor flushes the CPU data cache(s)?

  - by Durandal

  There is something that bugs me with the Java memory model (if i even understand everything correctly). If there are two threads A and B, there are no guarantees that B will ever see a value written by A, unless both A and B synchronize on the same monitor. For any system architecture that guarantees cache coherency between threads, there is no problem. But if the architecture does not support cache coherency in hardware, this essentially means that whenever a thread enters a monitor, all memory changes made before must be commited to main memory, and the cache must be invalidated. And it needs to be the entire data cache, not just a few lines, since the monitor has no information which variables in memory it guards. But that would surely impact performance of any application that needs to synchronize frequently (especially things like job queues with short running jobs). So can Java work reasonably well on architectures without hardware cache-coherency? If not, why doesn't the memory model make stronger guarantees about visibility? Wouldn't it be more efficient if the language would require information what is guarded by a monitor? As i see it the memory model gives us the worst of both worlds, the absolute need to synchronize, even if cache coherency is guaranteed in hardware, and on the other hand bad performance on incoherent architectures (full cache flushes). So shouldn't it be more strict (require information what is guarded by a monitor) or more lose and restrict potential platforms to cache-coherent architectures? As it is now, it doesn't make too much sense to me. Can somebody clear up why this specific memory model was choosen? EDIT: My use of strict and lose was a bad choice in retrospect. I used "strict" for the case where less guarantees are made and "lose" for the opposite. To avoid confusion, its probably better to speak in terms of stronger or weaker guarantees.

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• Help regarding multi-threading in MFC,please help me firends!

  - by kiddo

  Hello all,in my application there is a small part of function,in which it will read files to get some information,the number of filecount would be utleast 50,So I thought of implementing threading.Say if the user is giving 50 files,I wanted to separate it as 5 *10, 5 thread should be created,so that each thread can handle 10 files which can speed up the process.And also from the below code you can see that some variables are common.I read some articles about threading and I am aware that only one thread should access a variable/contorl at a me(CCriticalStiuation can be used for that).For me as a beginner,I am finding hard to imlplement what I have learned about threading.Somebody please give me some idea with code shown below..thanks in advance file read function:// void CMyClass::GetWorkFilesInfo(CStringArray& dataFilesArray,CString* dataFilesB, int* check,DWORD noOfFiles,LPWSTR path) { CString cFilePath; int cIndex =0; int exceptionInd = 0; wchar_t** filesForWork = new wchar_t*[noOfFiles]; int tempCheck; int localIndex =0; for(int index = 0;index < noOfFiles; index++) { tempCheck = *(check + index); if(tempCheck == NOCHECKBOX) { *(filesForWork+cIndex) = new TCHAR[MAX_PATH]; wcscpy(*(filesForWork+cIndex),*(dataFilesB +index)); cIndex++; } else//CHECKED or UNCHECKED { dataFilesArray.Add(*(dataFilesB+index)); *(check + localIndex) = *(check + index); localIndex++; } } WorkFiles(&cFilePath,dataFilesArray,filesForWork, path, cIndex); dataFilesArray.Add(cFilePath); *(check + localIndex) = CHECKED; }

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• Ajax post failing in asp

  - by Dave Kiss

  hey guys, this might be really stupid, but hopefully someone can help. I'm trying to post to an external script using ajax so i can mail the data, but for some reason my data is not making it to the script. $(document).ready(function() { $("#submitContactForm").click(function () { $('#loading').append('<img src="http://www.xxxxxxxx.com/demo/copyshop/images/loading.gif" alt="Currently Loading" id="loadingComment" />'); var name = $('#name').val(); var email = $('#email').val(); var comment = $('#comment').val(); var dataString = 'name='+ name + '&email=' + email + '&comment=' + comment; $.ajax({ url: 'http://www.xxxxx.com/demo/copyshop/php/sendmail.php', type: 'POST', data: '?name=Dave&[email protected]&comment=hiiii', success: function(result) { $('#loading').append('success'); } }); return false; }); }); the php script is simple (for now - just wanted to make sure it worked) <?php $name = $_POST['name']; $email = $_POST['email']; $comment = $_POST['comment']; $to = '[email protected]'; $subject = 'New Contact Inquiry'; $message = $comment; mail($to, $subject, $message); ?> the jquery is embedded in an .aspx page (a language i'm not familiar with) but is posting to a php script. i'm receiving emails properly but there is no data inside. am i missing something? i tried to bypass the variables in this example, but its still not working thanks

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• C++ privately contructed class

  - by Nona Urbiz

  How can I call a function and keep my constructor private? If I make the class static, I need to declare an object name which the compiler uses to call the constructor, which it cannot if the constructor is private (also the object would be extraneous). Here is the code I am attempting to use (it is not compilable): I want to keep the constructor private because I will later be doing a lot of checks before adding an object, modifying previous objects when all submitted variables are not unique rather than creating new objects. #include <iostream> #include <fstream> #include <regex> #include <string> #include <list> #include <map> using namespace std; using namespace tr1; class Referral { public: string url; map<string, int> keywords; static bool submit(string url, string keyword, int occurrences) { //if(Referrals.all.size == 0){ // Referral(url, keyword, occurrences); //} } private: list<string> urls; Referral(string url, string keyword, int occurrences) { url = url; keywords[keyword] = occurrences; Referrals.all.push_back(this); } }; struct All { list<Referral> all; }Referrals; int main() { Referral.submit("url", "keyword", 1); }

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• Read large amount of data from file in Java

  - by Crozin

  Hello I've got text file that contains 1 000 002 numbers in following formation: 123 456 1 2 3 4 5 6 .... 999999 100000 Now I need to read that data and allocate it to int variables (the very first two numbers) and all the rest (1 000 000 numbers) to an array int[]. It's not a hard task, but - it's horrible slow. My first attempt was java.util.Scanner: Scanner stdin = new Scanner(new File("./path")); int n = stdin.nextInt(); int t = stdin.nextInt(); int array[] = new array[n]; for (int i = 0; i < n; i++) { array[i] = stdin.nextInt(); } It works as excepted but it takes about 7500 ms to execute. I need to fetch that data in up to several hundred of milliseconds. Then I tried java.io.BufferedReader: Using BufferedReader.readLine() and String.split() I got the same results in about 1700 ms, but it's still too many. How can I read that amount of data in less that 1 second? The final result should be equal to: int n = 123; int t = 456; int array[] = { 1, 2, 3, 4, ..., 999999, 100000 };

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• C++ AMP, for loops to parallel_for_each loop

  - by user1430335

  I'm converting an algorithm to make use of the massive acceleration that C++ AMP provides. The stage I'm at is putting the for loops into the known parallel_for_each loop. Normally this should be a straightforward task to do but it appears more complex then I first thought. It's a nested loop which I increment using steps of 4 per iterations: for(int j = 0; j < height; j += 4, data += width * 4 * 4) { for(int i = 0; i < width; i += 4) { The trouble I'm having is the use of the index. I can't seem to find a way to properly fit this into the parallel_for_each loop. Using an index of rank 2 is the way to go but manipulating it via branching will do harm to the performance gain. I found a similar post: Controlling the index variables in C++ AMP. It also deals about index manipulation but the increment aspect doesn't cover my issue. With kind regards, Forcecast

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• Overwriting a range of bits in an integer in a generic way

  - by porgarmingduod

  Given two integers X and Y, I want to overwrite bits at position P to P+N. Example: int x = 0xAAAA; // 0b1010101010101010 int y = 0x0C30; // 0b0000110000110000 int result = 0xAC3A; // 0b1010110000111010 Does this procedure have a name? If I have masks, the operation is easy enough: int mask_x = 0xF00F; // 0b1111000000001111 int mask_y = 0x0FF0; // 0b0000111111110000 int result = (x & mask_x) | (y & mask_y); What I can't quite figure out is how to write it in a generic way, such as in the following generic C++ function: template<typename IntType> IntType OverwriteBits(IntType dst, IntType src, int pos, int len) { // If: // dst = 0xAAAA; // 0b1010101010101010 // src = 0x0C30; // 0b0000110000110000 // pos = 4 ^ // len = 8 ^------- // Then: // result = 0xAC3A; // 0b1010110000111010 } The problem is that I cannot figure out how to make the masks properly when all the variables, including the width of the integer, is variable. Does anyone know how to write the above function properly?

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• C++: Declare static variable in function argument list

  - by MDC

  Is there any way at all in C++ to declare a static variable while passing it to a function? I'm looking to use a macro to expand to the expression passed to the function. The expression needs to declare and initialize a static variable on that particular line (based on the filename and line number using FILE and LINE). int foo(int b) { int c = b + 2; return c; } int main() { int a = 3; a = foo(static int h = 2); //<---- see this! cout << a; return 0; } The problem I'm trying to solve is getting the filename and line number with the FILE and LINE macros provided by the preprocessor, but then creating a lookup table with integer keys leading to the FILE, LINE pairs. For example, the key 89 may map to file foo.cpp, line 20. To get this to work, I'm trying to use local static variables, so that they are initialized only once per line execution. The static variable will be initialized by calling a function that calculates the integer key and adds an entry to the lookup table if it is not there. Right now the program uses a message class to send exception information. I'm writing a macro to wrap this class into a new class: WRAPPER_MACRO(old_class_object) will expand to NewClass(old_class_object, key_value). If I add the static variable declaration as a second line right before this, it should work. The problem is that in most places in the code, the old class object is passed as an argument to a function. So the problem becomes declaring and initializing the static variable somehow with the macro, while keeping the existing function calls.

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• Could someone help me debug my app (not very big)?

  - by Alex

  Not sure if this kind of help is accepted to ask for here, tell me if it isn't. It has to get done before tomorrow, it's not entirerly finished but it should work somewhat ok by now. I'm trying to use the Eclipse debugger (not very used to it). I have my top-level or main class, which is Game, in which I have a constructor and a main method. In the main method I create a new "Game", initiating the constructor. public static void main(String[] args){ Game chess = new Game(); } public Game(){ Board board = new Board(); That's the first thing the debugger reacts to: Thread [main] (Suspended) ClassNotFoundException(Object).<init>() line: 20 [local variables unavailable] ClassNotFoundException(Throwable).<init>(String, Throwable) line: 217 ClassNotFoundException(Exception).<init>(String, Throwable) line: not available ClassNotFoundException.<init>(String) line: not available URLClassLoader$1.run() line: not available AccessController.doPrivileged(PrivilegedExceptionAction<T>, AccessControlContext) line: not available [native method] Launcher$ExtClassLoader(URLClassLoader).findClass(String) line: not available Launcher$ExtClassLoader.findClass(String) line: not available Launcher$ExtClassLoader(ClassLoader).loadClass(String, boolean) line: not available Launcher$AppClassLoader(ClassLoader).loadClass(String, boolean) line: not available Launcher$AppClassLoader.loadClass(String, boolean) line: not available Launcher$AppClassLoader(ClassLoader).loadClass(String) line: not available Game.<init>() line: 15 Game.main(String[]) line: 11 Line 11 is the one line in my main method, line 15 is the instantiation of "board".

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• Prolog Beginner: How to unify with arithmentic cmparison operators or how to get a set var to range

  - by sixtyfootersdude

  I am new to prolog. I need to write an integer adder that will add numbers between 0-9 to other numbers 0-9 and produce a solution 0-18. This is what I want to do: add(in1, in2, out) :- in1 < 10, in2 < 10, out < 18. I would like to be able to call it like this: To Check if it is a valid addition: ?- add(1,2,3). true ?- add(1,2,4). false With one missing variable: ?- add(X,2,3). 1 ?- add(1,4,X). 5 With multiple missing variables: ?-add(X,Y,Z). % Some output that would make sense. Some examples could be: X=1, Y=1, Z=2 ; X=2, Y=1, Z=3 ...... I realize that this is probably a pretty simplistic question and it is probably very straightforward. However cording to the prolog tutorial I am using: "Unlike unification Arithmetic Comparison Operators operators cannot be used to give values to a variable. The can only be evaluated when every term on each side have been instantiated."

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• Hiding Url for asp.net page

  - by user204588

  Hello, I'm creating an html page that is posted to another page for processing. I don't want users to see the weird URL they are redirected to and I was using FRAMES but I can't figure out how to add my HTML page dynamically because I need the variables and either add frames or try another way to accomplish this. So, based on how I'm creating the page below, how can I hide the URL and add something that I want. Here is how I'm creating the page. StringBuilder sb = new StringBuilder(); sb.Append("<html><head></head>"); sb.Append("<body onload=\"document.frmLaunch.submit();\">"); sb.Append("<form name=\"frmLaunch\" action=\"" + variableTargetURL + "\" method=\"post\">"); sb.Append("<input type=hidden name=\"testVariable\" value=\"" + variableTest + "\">"); sb.Append("</form>"); sb.Append("</body></html>"); HttpResponse response = HttpContext.Current.Response; response.Clear(); response.Write(sb.ToString()); response.End();

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• Please tell me what is wrong with my threading!!!

  - by kiddo

  I have a function where I will compress a bunch of files into a single compressed file..it is taking a long time(to compress),so I tried implementing threading in my application..Say if I have 20 files for compression,I separated that as 5*4=20,inorder to do that I have separate variables(which are used for compression) for all 4 threads in order to avoid locks and I will wait until the 4 thread finishes..Now..the threads are working but i see no improvement in their performance..normally it will take 1 min for 20 files(for example) after implementing threading ...there is only 5 or 3 sec difference., sometimes the same. here i will show the code for 1 thread(so it is for other3 threads) //main thread myClassObject->thread1 = AfxBeginThread((AFX_THREADPROC)MyThreadFunction1,myClassObject); .... HANDLE threadHandles[4]; threadHandles[0] = myClassObject->thread1->m_hThread; .... WaitForSingleObject(myClassObject->thread1->m_hThread,INFINITE); UINT MyThreadFunction(LPARAM lparam) { CMerger* myClassObject = (CMerger*)lparam; CString outputPath = myClassObject->compressedFilePath.GetAt(0);//contains the o/p path wchar_t* compressInputData[] = {myClassObject->thread1outPath, COMPRESS,(wchar_t*)(LPCTSTR)(outputPath)}; HINSTANCE loadmyDll; loadmydll = LoadLibrary(myClassObject->thread1outPath); fp_Decompress callCompressAction = NULL; int getCompressResult=0; myClassObject->MyCompressFunction(compressInputData,loadClient7zdll,callCompressAction,myClassObject->thread1outPath, getCompressResult,minIndex,myClassObject->firstThread,myClassObject); return 0; }

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• C++ gdb GUI

  - by HappyDude

  Briefly: Does anyone know of a GUI for gdb that brings it on par or close to the feature set you get in the more recent version of Visual C++? In detail: As someone who has spent a lot of time programming in Windows, one of the larger stumbling blocks I've found whenever I have to code C++ in Linux is that debugging anything using commandline gdb takes me several times longer than it does in Visual Studio, and it does not seem to be getting better with practice. Some things are just easier or faster to express graphically. Specifically, I'm looking for a GUI that: Handles all the basics like stepping over & into code, watch variables and breakpoints Understands and can display the contents of complex & nested C++ data types Doesn't get confused by and preferably can intelligently step through templated code and data structures while displaying relevant information such as the parameter types Can handle threaded applications and switch between different threads to step through or view the state of Can handle attaching to an already-started process or reading a core dump, in addition to starting the program up in gdb If such a program does not exist, then I'd like to hear about experiences people have had with programs that meet at least some of the bullet points. Does anyone have any recommendations? Edit: Listing out the possibilities is great, and I'll take what I can get, but it would be even more helpful if you could include in your responses: (a) Whether or not you've actually used this GUI and if so, what positive/negative feedback you have about it. (b) If you know, which of the above-mentioned features are/aren't supported Lists are easy to come by, sites like this are great because you can get an idea of people's personal experiences with applications.

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• Extracting exported functions out of a shared lib (ubuntu)

  - by Pingu

  the title already describes my problem. I found this post, but it didn't completely answers my question. With the help of it i got this output from nm... $nm -C -g -D ./libLoggingHandler.so 000000cc A _DYNAMIC ... 000042e0 T write_str(char*, char const*, int*) 00005a78 T RingBuffer::WriteUnlock() ... 00005918 T TraceLines::GetItemSize() ... U SharedMemory::attach(int, void const*, int) ... 00003810 T TraceProfile::FindLineNr(int, int) ... 00002d40 T LoggingHandler::getLogLevel() ... U SharedResource::getSharedResourceKey(char const*, int) ... which are the exported functions? I already found a hint in this post, that the "T" indicates that its getting exported. But if i check the nm manual here, it just says T - The symbol is in the text (code) section. My questions is: Does this output give me the information which functions are exported functions (or variables)? If not, how do i get it? Greetings, Pingu

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• Persisting object changes from child form to parent form based on button press.

  - by Shyran

  I have created a form that is used for both adding and editing a custom object. Which mode the form takes is provided by an enum value passed from the calling code. I also pass in an object of the custom type. All of my controls at data bound to the specific properties of the custom object. When the form is in Add mode, this works great as when the controls are updated with data, the underlying object is as well. However, in Edit mode, I keep two variables of the custom object supplied by the calling code, the original, and a temporary one made through deep copying. The controls are then bound to the temporary copy, this makes it easy to discard the changes if the user clicks the Cancel button. What I want to know is how to persist those changes back to the original object if the user clicks the OK button, since there is now a disconnect because of the deep copying. I am trying to avoid implementing a internal property on the Add/Edit form if I can. Below is an example of my code: public AddEditCustomerDialog(Customer customer, DialogMode mode) { InitializeComponent(); InitializeCustomer(customer, mode); } private void InitializeCustomer(Customer customer, DialogMode mode) { this.customer = customer; if (mode == DialogMode.Edit) { this.Text = "Edit Customer"; this.tempCustomer = ObjectCopyHelper.DeepCopy(this.customer); this.customerListBindingSource.DataSource = this.tempCustomer; this.phoneListBindingSource.DataSource = this.tempCustomer.PhoneList; } else { this.customerListBindingSource.DataSource = this.customer; this.phoneListBindingSource.DataSource = this.customer.PhoneList; } }

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• Can a member struct be zero-init from the constructor initializer list without calling memset?

  - by selbie

  Let's say I have the following structure declaration (simple struct with no constructor). struct Foo { int x; int y; int z; char szData[DATA_SIZE]; }; Now let's say this struct is a member of a C++ class as follows: class CFoobar { Foo _foo; public: CFoobar(); }; If I declare CFoobar's constructor as follows: CFoobar::CFoobar() { printf("_foo = {%d, %d, %d}\n", _foo.x, _foo.y,_foo.z); for (int x = 0; x < 100; x++) printf("%d\n", _foo.szData[x]); } As you would expect, when CFoobar's constructor runs, garbage data gets printed out Obviously, the easy fix is to memset or ZeroMemory &_foo. It's what I've always done... However, I did notice that if add _foo to the constructor's initialization list with no parameters as follows: CFoobar::CFoobar() : _foo() { That this appears to zero-out the member variables of _foo. At least that was the case with g++ on linux. Now here's my question: Is this standard C++, or is this compiler specific behavior? If it's standard behavior, can someone quote me a reference from an official source? Any "gotchas" in regards to implicit zero-init behavior with more complicated structs and classes?

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• NullPointerException on Activity Testint Tutorial

  - by Bendik

  Hello, I am currently trying the activity testing tutorial (Found here), and have a problem. It seems that whenever I try to call something inside the UIThread, I get a java.lang.NullPointerException. public void testSpinnerUI() { mActivity.runOnUiThread( new Runnable() { public void run() { mSpinner.requestFocus(); } }); } This gives me: Incomplete: java.lang.NullPointerException and nothing else. I have tried this on two different samples now, with the same result. I tried with a try/catch clause around the mSpinner.requestFocus() call, and it seems that mSpinner is null inside the thread. I have set it properly up with the setUp() function found in the same sample, and a quick assertNotNull( mSpinner ) shows me that mSpinner is in fact not null after the setUp() function. What can be the cause of this? EDIT; ok, some more testing has been done. It seems that the application that is being tested resets between each test. This essentially makes me have to reinstantiate all variables between each test. Is this normal?

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• Mathematics errors in basic C++ program

  - by H Bomb1013

  I am working with a basic C++ program to determine the area and perimeter of a rectangle. My program works fine for whole numbers but falls apart when I use any number with a decimal. I get the impression that I am leaving something out, but since I'm a complete beginner, I have no idea what. Below is the source: #include <iostream> using namespace std; int main() { // Declared variables int length; // declares variable for length int width; // declares variable for width int area; // declares variable for area int perimeter; // declares variable for perimeter // Statements cout << "Enter the length and the width of the rectangle: "; // states what information to enter cin >> length >> width; // user input of length and width cout << endl; // closes the input area = length * width; // calculates area of rectangle perimeter = 2 * (length + width); //calculates perimeter of rectangle cout << "The area of the rectangle = " << area << " square units." <<endl; // displays the calculation of the area cout << "The perimeter of the rectangle = " << perimeter << " units." << endl; // displays the calculation of the perimeter system ("pause"); // REMOVE BEFORE RELEASE - testing purposes only return 0; }

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• Getting information from servlet created html

  - by user541597

  I have a servlet that creates an html text box and then redirects to another servlet on submit. How can I access the value of the html text box from the new servlet? I am able to access servlet variables from the new servlet but I am not aware of how to access the value of the html generated code. thanks, Here is the servlet that gets the text input public class ServletB extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); String value = System.getProperty("card"); PrintWriter out = response.getWriter(); out.println("<center><h1>Your preffered method of payment is "+value+"</h1><br />"); out.println("Please Enter Card Number<input type =\"text\" name = \"number\"/><form action=\"http://codd.cs.gsu.edu:9999/cpereyra183/servlet/ServletC\"><input type =\"submit\" value=\"Continue\" /><input type=\"button\" value=\"Cancel\" /></center>"); } }} This is the servlet the first servlet redirects to all I do is try to do is output the text input public class ServletC extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { response.setContentType("text/html"); String value = System.getProperty("card"); PrintWriter out = response.getWriter(); out.println(request.getParameter("number")); } }

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