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• VERY simple C program won't compile with VC 64

  - by Paperflyer

  Here is a very simple C program: #include <stdio.h> int main (int argc, char *argv[]) { printf("sizeof(short) = %d\n",(int)sizeof(short)); printf("sizeof(int) = %d\n",(int)sizeof(int)); printf("sizeof(long) = %d\n",(int)sizeof(long)); printf("sizeof(long long) = %d\n",(int)sizeof(long long)); printf("sizeof(float) = %d\n",(int)sizeof(float)); printf("sizeof(double) = %d\n",(int)sizeof(double)); return 0; } While it compiles fine on Win32 (command line: cl main.c), it does not using the Win64 compiler ("c:\Program Files(x86)\Microsoft Visual Studio 9.0\VC\bin\amd64\cl.exe" main.c). Specifically, it sais "error LNK2019: unresolved external symbol printf referenced in function main". As far as I understand this, it can not link to printf, right? Obviously, I have Microsoft Visual C++ Compiler 2008 (Standard enu) x86 and x64 installed and am using the 64-bit flavor of Windows (7). What is the problem here?

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• QT: I've inherited from QTreeView. I've inherited from QStandardItem. How do i Style the items?

  - by San Jacinto

  My Google skills must be failing me today. I've inherited from QTreeView to create a TreeView that stores a QStandardItemModel instead of a QAbstractItemModel. I have also inherited from QStandardItem to create a class to store my data in an item as is necessary. I've successfully inserted my derived QStandardItem into my derived QTreeView's QStandardItemModel. Now the trouble is, I can't figure out how to style it. I know that QTreeView has a setStyleSheet(QString) member, but I can't seem to get it working. It may be as simple as I'm not styling the correct attribute. Any pointers would be appreciated. Thanks. For clarity, here are my class defs. class SurveyTreeItem : public QStandardItem { public: SurveyTreeItem(); SurveyTreeItem( const QString & text ); ~SurveyTreeItem(); }; class StandardItemModelTreeView : public QTreeView { public: StandardItemModelTreeView(QWidget* parent = 0); ~StandardItemModelTreeView(); QStandardItemModel* getStandardItemModel(); }; I've tried the following StyleSheets: StandardTreeView::Item { font: 87 12pt 'Arial Black'; } StandardTreeView::QStandardItem { font: 87 12pt 'Arial Black'; } QTreeView::QStandardItem { font: 87 12pt 'Arial Black'; } QTreeView::Item { font: 87 12pt 'Arial Black'; } QTreeView::SurveyTreeItem { font: 87 12pt 'Arial Black'; } StandardTreeView::SurveyTreeItem { font: 87 12pt 'Arial Black'; }

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• debugging finite state machine spell checker code

  - by Durell

  I need someone to debug the lines of c++ code I wrote below so it can run. It is intended to spell check the word "and" using state to state transition. include include using namespace std; string in_str; int n; void spell_check() { int i; FILE *in_file; while (!EOF(in_file)) { fscanf(in_str); n = strlen(in_str); start(in_str,n); } } void start() { char next_char; int i = 0; if (n == 0) { cout<<"This is an empty string"; exit();//do something here to terminate the program } else{ next_char = in_str[i]; if(next_char == 'a') { i++; if(i >= n) error(); else state_A(i); } else error(); } } void state_A(int i) { if(in_str[i] == 'n') { i++; if(i void state_AN(int i) { if(in_str[i] == 'd') { if(i == n-1) cout<<" Your keyword spelling is correct"; else cout<<"Wrong keyword spelling"; } } int main() { spell_check(); return 0; }

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• Facade Design Patterns and Subclassing

  - by Code Sherpa

  Hi. I am using a facade design pattern for a C# program. The program basically looks like this... public class Api { #region Constants private const int version = 1; #endregion #region Private Data private XProfile _profile; private XMembership _membership; private XRoles _role; #endregion Private Data public Api() { _membership = new XMembership(); _profile = new XProfile(); _role = new XRoles(); } public int GetUserId(string name) { return _membership.GetIdByName(name); } } Now, as I would like subclass my methods into three categories: Role, Profile, and Member. This will be easier on the developers eye because both Profile and Membership expose a lot of methods that look similar (and a few by Role). For example, getting a user's ID would look like: int _id = Namespace.Api.Member.GetUserId("Henry222"); Can somebody "illustrate" how subclassing should work in this case to achieve the effect I am looking for? Thanks in advance.

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• C malloc assertion help

  - by Chris

  I am implementing a divide and conquer polynomial algorithm so i can bench it against an opencl implementation, but i can't seem to get malloc to work. When I run the program it allocates a bunch of stuff, checks some things, then sends the size/2 to the algorithm. Then when I hit the malloc line again it spits out this: malloc.c:3096: sYSMALLOc: Assertion `(old_top == (((mbinptr) (((char *) &((av)-bins[((1) - 1) * 2])) - __builtin_offsetof (struct malloc_chunk, fd)))) && old_size == 0) || ((unsigned long) (old_size) = (unsigned long)((((__builtin_offsetof (struct malloc_chunk, fd_nextsize))+((2 * (sizeof(size_t))) - 1)) & ~((2 * (sizeof(size_t))) - 1))) && ((old_top)-size & 0x1) && ((unsigned long)old_end & pagemask) == 0)' failed. Aborted The line in question is: int *out, .....other vars....; out = (int *)malloc(sizeof(int) * size * 2); I have checked size with fprintf and it is a positive int (usually 50 at that point). I have tried calling malloc with a plain number as well and i still get the error. I'm just stumped at what's going on, and nothing from google that I have found so far has been too helpful. Any ideas what's going on? I'm trying to figure out how to compile a newer GCC in case it's a compiler error, but i really doubt it.

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• Vector of pointers to base class, odd behaviour calling virtual functions

  - by Ink-Jet

  I have the following code #include <iostream> #include <vector> class Entity { public: virtual void func() = 0; }; class Monster : public Entity { public: void func(); }; void Monster::func() { std::cout << "I AM A MONSTER" << std::endl; } class Buddha : public Entity { public: void func(); }; void Buddha::func() { std::cout << "OHMM" << std::endl; } int main() { const int num = 5; // How many of each to make std::vector<Entity*> t; for(int i = 0; i < num; i++) { Monster m; Entity * e; e = &m; t.push_back(e); } for(int i = 0; i < num; i++) { Buddha b; Entity * e; e = &b; t.push_back(e); } for(int i = 0; i < t.size(); i++) { t[i]->func(); } return 0; } However, when I run it, instead of each class printing out its own message, they all print the "Buddha" message. I want each object to print its own message: Monsters print the monster message, Buddhas print the Buddha message. What have I done wrong?

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• Non-blocking TCP buffer issues.

  - by Poni

  Hi! I think I'm in a problem. I have two TCP apps connected to each other which use winsock I/O completion ports to send/receive data (non-blocking sockets). Everything works just fine until there's a data transfer burst. The sender starts sending incorrect/malformed data. I allocate the buffers I'm sending on the stack, and if I understand correctly, that's a wrong to do, because these buffers should remain as I sent them until I get the "write complete" notification from IOCP. Take this for example: void some_function() { char cBuff[1024]; // filling cBuff with some data WSASend(...); // sending cBuff, non-blocking mode // filling cBuff with other data WSASend(...); // again, sending cBuff // ..... and so forth! } If I understand correctly, each of these WSASend() calls should have its own unique buffer, and that buffer can be reused only when the send completes. Correct? Now, what strategies can I implement in order to maintain a big sack of such buffers, how should I handle them, how can I avoid performance penalty, etc'? And, if I am to use buffers that means I should copy the data to be sent from the source buffer to the temporary one, thus, I'd set SO_SNDBUF on each socket to zero, so the system will not re-copy what I already copied. Are you with me? Please let me know if I wasn't clear.

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• Empty data problem - data layer or DAL?

  - by luckyluke

  I designing the new App now and giving the following question a lot of thought. I consume a lot of data from the warehouse, and the entities have a lot of dictionary based values (currency, country, tax-whatever data) - dimensions. I cannot be assured though that there won't be nulls. So I am thinking: create an empty value in each of teh dictionaries with special keyID - ie. -1 do the ETL (ssis) do the correct stuff and insert -1 where it needs to let the DAL know that -1 is special (Static const whatever thing) don't care in the code to check for nullness of dictionary entries because THEY will always have a value But maybe I should be thinking: import data AS IS let the DAL do the thinking using empty record Pattern still don't care in the code because business layer will have what it needs from DAL. I think is more of a approach thing but maybe i am missing something important here... What do You think? Am i clear? Please don't confuse it with empty record problem. I do use emptyCustomer think all the time and other defaults too.

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• Run a .java file using ProcessBuilder

  - by David K

  I'm a novice programmer working in Eclipse, and I need to get multiple processes running (this is going to be a simulation of a multi-computer system). My initial hackup used multiple threads to multiple classes, but now I'm trying to replace the threads with processes. From my reading, I've gleaned that ProcessBuilder is the way to go. I have tried many many versions of the input you see below, but cannot for the life of me figure out how to properly use it. I am trying to run the .java files I previously created as classes (which I have modified). I eventually just made a dummy test.java to make sure my process is working properly - its only function is to print that it ran. My code for the two files are below. Am I using ProcessBuilder correctly? Is this the correct way to read the output of my subprocess? Any help would be much appreciated. David primary process package Control; import java.io.*; import java.lang.*; public class runSPARmatch { /** * @param args */ public static void main(String args[]) { try { ProcessBuilder broker = new ProcessBuilder("javac.exe","test.java","src\\Broker\\"); Process runBroker = broker.start(); Reader reader = new InputStreamReader(runBroker.getInputStream()); int ch; while((ch = reader.read())!= -1) System.out.println((char)ch); reader.close(); runBroker.waitFor(); System.out.println("Program complete"); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } subprocess package Broker; public class test { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub System.out.println("This works"); } }

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• Memory leak problem. iPhone SDK

  - by user326375

  Hello, i've got a problem, i cannot solve it, just recieving error: Program received signal: “0”. The Debugger has exited due to signal 10 (SIGBUS).The Debugger has exited due to signal 10 (SIGBUS). Here is some method, if i comment it out, problem goes aways - (void)loadTexture { const int num_tex = 10; glGenTextures(num_tex, &textures[0]); //TEXTURE #1 textureImage[0] = [UIImage imageNamed:@"wonder.jpg"].CGImage; //TEXTURE #2 textureImage[1] = [UIImage imageNamed:@"wonder.jpg"].CGImage; //TEXTURE #3 textureImage[2] = [UIImage imageNamed:@"wall_eyes.jpg"].CGImage; //TEXTURE #4 textureImage[3] = [UIImage imageNamed:@"wall.jpg"].CGImage; //TEXTURE #5 textureImage[4] = [UIImage imageNamed:@"books.jpg"].CGImage; //TEXTURE #6 textureImage[5] = [UIImage imageNamed:@"bush.jpg"].CGImage; //TEXTURE #7 textureImage[6] = [UIImage imageNamed:@"mushroom.jpg"].CGImage; //TEXTURE #8 textureImage[7] = [UIImage imageNamed:@"roots.jpg"].CGImage; //TEXTURE #9 textureImage[8] = [UIImage imageNamed:@"roots.jpg"].CGImage; //TEXTURE #10 textureImage[9] = [UIImage imageNamed:@"clean.jpg"].CGImage; for(int i=0; i<num_tex; i++) { NSInteger texWidth = CGImageGetWidth(textureImage[i]); NSInteger texHeight = CGImageGetHeight(textureImage[i]); GLubyte *textureData = (GLubyte *)malloc(texWidth * texHeight * 4); CGContextRef textureContext = CGBitmapContextCreate(textureData, texWidth, texHeight, 8, texWidth * 4, CGImageGetColorSpace(textureImage[i]), kCGImageAlphaPremultipliedLast); CGContextDrawImage(textureContext, CGRectMake(0.0, 0.0, (float)texWidth, (float)texHeight), textureImage[i]); CGContextRelease(textureContext); glBindTexture(GL_TEXTURE_2D, textures[i]); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, textureData); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); free(textureData); } } anyone can help me with releasing/deleting objects in this method? Thanks.

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• 'strcpy' error and warning

  - by Leejo

  I'm getting a 'strcpy' error and warning for the following lines: _tcscpy(strCommandLine,_T("MyProgram.exe /param1")); _tcscpy(strApplicationName,_T("MyProgram.exe")); Not sure why I'm getting a 'strcpy' error or warning since I'm not using 'strcpy'. The only lines related to this is: LPCTSTR strApplicationName; LPTSTR strCommandLine; _tcscpy(strCommandLine,_T("MyProgram.exe /param1")); //warning is on this line _tcscpy(strApplicationName,_T("MyProgram.exe")); //error is on this line The output is: 1c:\documents and settings\X.X\my documents\sandbox\sample.cpp(52) : warning C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details. 1 c:\program files\microsoft visual studio 8\vc\include\string.h(74) : see declaration of 'strcpy' 1c:\documents and settings\X.X\my documents\sandbox\sample.cpp(53) : error C2664: 'strcpy' : cannot convert parameter 1 from 'LPCTSTR' to 'char *' 1 Conversion loses qualifiers Any ideas on what this could means? These are my headers: iostream windows.h stdio.h tchar.h winnt.h

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• How to invalidate cache when benchmarking?

  - by Michael Buen

  I have this code, that when swapping the order of UsingAs and UsingCast, their performance also swaps. using System; using System.Diagnostics; using System.Linq; using System.IO; class Test { const int Size = 30000000; static void Main() { object[] values = new MemoryStream[Size]; UsingAs(values); UsingCast(values); Console.ReadLine(); } static void UsingCast(object[] values) { Stopwatch sw = Stopwatch.StartNew(); int sum = 0; foreach (object o in values) { if (o is MemoryStream) { var m = (MemoryStream)o; sum += (int)m.Length; } } sw.Stop(); Console.WriteLine("Cast: {0} : {1}", sum, (long)sw.ElapsedMilliseconds); } static void UsingAs(object[] values) { Stopwatch sw = Stopwatch.StartNew(); int sum = 0; foreach (object o in values) { if (o is MemoryStream) { var m = o as MemoryStream; sum += (int)m.Length; } } sw.Stop(); Console.WriteLine("As: {0} : {1}", sum, (long)sw.ElapsedMilliseconds); } } Outputs: As: 0 : 322 Cast: 0 : 281 When doing this... UsingCast(values); UsingAs(values); ...Results to this: Cast: 0 : 322 As: 0 : 281 When doing just this... UsingAs(values); ...Results to this: As: 0 : 322 When doing just this: UsingCast(values); ...Results to this: Cast: 0 : 322 Aside from running them independently, how to invalidate the cache so the second code being benchmarked won't receive the cached memory of first code? Benchmarking aside, just loved the fact that modern processors do this caching magic :-)

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• Printing double variable contents

  - by Adil

  I tried following code snippet and output is surprising me: #include <stdio.h> #include <math.h> int main() { double num; unsigned char ch; ch = 19; num = 1.0E+20 ; num += ch * 1.0E+18; printf("E18 = %lf \n",num); printf("E18 = %e \n",num); num = 11.0E+21 ; num += ch * 1.0E+19; printf("E19 = %lf <------\n",num); printf("E19 = %e <------\n",num); num = 11.0E+22 ; num += ch * 1.0E+20; printf("E20 = %lf\n",num); printf("E20 = %e\n",num); num = 11.0E+23 ; num += ch * 1.0E+21; printf("E21 = %lf\n",num); printf("E21 = %e\n",num); num = 11.0E+24 ; num += ch * 1.0E+22; printf("E22 = %lf <------\n",num); printf("E22 = %e <------\n",num); return 0; } The output of the program: E18 = 119000000000000000000.000000 E18 = 1.190000e+20 E19 = 11190000000000000524288.000000 <------ E19 = 1.119000e+22 <------ E20 = 111900000000000001048576.000000 E20 = 1.119000e+23 E21 = 1119000000000000044040192.000000 E21 = 1.119000e+24 E22 = 11189999999999999366660096.000000 <------ E22 = 1.119000e+25 <------ Why the data corrupted when printed while in exponent form its OK

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• Powershell Regex help in extracting text between strings

  - by vivekeviv

  i Have an arguments like the one below which i pass to powershell script -arg1 -abc -def -arg2 -ghi -jkl -arg3 -123 -234 Now i need to extract three strings without any whitespace string 1: "-abc -def" string 2: "-ghi -jkl" string 3: "-123 -234" i figured this expression could do it. But this doesnt seem to work. $args -match '-arg1(?'arg1'.*?) -arg3(?'arg3'.*?) -arg3(?'arg3'.*)'. THis should return $matches['arg1'] etc. So whats wrong in above expression. Why do i get an error as shown below runScript.ps1 -arg1 -abc -def -arg2 -ghi -jkl -arg3 -123 -234 Unexpected token 'arg1'.?) -arg2 (?'arg2'.?) -arg3 (?'arg3'.)'' in expression or statement. At G:\powershell\tools\powershell\runTest.ps1:1 char:71 + $args -match '-arg1 (?'arg1'.?) -arg2 (?'arg2'.?) -arg3 (?'arg3'.)' <<<< + CategoryInfo : ParserError: (arg1'.?) -arg2...g3 (?'arg3'.)':String) [], ParseException + FullyQualifiedErrorId : UnexpectedToken and also the second question is how do i make arg1 or arg2 or arg3 optional? The argument to script can be -arg2 -def -ghi. I'll take some default values for arg(1|2|3) that is not mentioned. Thanks

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• How to properly implement cheat codes?

  - by Axarydax

  Hi, what would be the best way to implement kind of cheat codes in general? I have WinForms application in mind, where a cheat code would unlock an easter egg, but the implementation details are not relevant. The best approach that comes to my mind is to keep index for each code - let's consider famous DOOM codes - IDDQD and IDKFA, in a fictional C# app. string[] CheatCodes = { "IDDQD", "IDKFA"}; int[] CheatIndexes = { 0, 0 }; const int CHEAT_COUNT = 2; void KeyPress(char c) { for (int i = 0; i < CHEAT_COUNT; i++) //for each cheat code { if (CheatCodes[i][CheatIndexes[i]] == c) { //we have hit the next key in sequence if (++CheatIndexes[i] == CheatCodes[i].Length) //are we in the end? { //Do cheat work MessageBox.Show(CheatCodes[i]); //reset cheat index so we can enter it next time CheatIndexes[i] = 0; } } else //mistyped, reset cheat index CheatIndexes[i] = 0; } } Is this the right way to do it?

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• Output iterator's value_type

  - by wilhelmtell

  The STL commonly defines an output iterator like so: template<class Cont> class insert_iterator : public iterator<output_iterator_tag,void,void,void,void> { // ... Why do output iterators define value_type as void? It would be useful for an algorithm to know what type of value it is supposed to output. For example, a function that translates a URL query "key1=value1&key2=value2&key3=value3" into any container that holds key-value strings elements. template<typename Ch,typename Tr,typename Out> void parse(const std::basic_string<Ch,Tr>& str, Out result) { std::basic_string<Ch,Tr> key, value; // loop over str, parse into p ... *result = typename iterator_traits<Out>::value_type(key, value); } The SGI reference page of value_type hints this is because it's not possible to dereference an output iterator. But that's not the only use of value_type: I might want to instantiate one in order to assign it to the iterator.

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• Issue with clipping rectangles and back to front rendering

  - by Milo

  Here is my problem. My rendering algorithm renders from back to front. But logically, clipping rectangles need to be applied from front to back. Hence why the following does not work: void AguiWidgetManager::recursiveRender(const AguiWidget *root) { //recursively calls itself to render widgets from back to front AguiWidget* nonConstRoot = (AguiWidget*)root; if(!nonConstRoot->isVisable()) { return; } //push the clipping rectangle if(nonConstRoot->isClippingChildren()) { graphicsContext->pushClippingRect(nonConstRoot->getClippingRectangle()); } if(nonConstRoot->isEnabled()) { nonConstRoot->paint(AguiPaintEventArgs(true,graphicsContext)); for(std::vector<AguiWidget*>::const_iterator it = root->getPrivateChildBeginIterator(); it != root->getPrivateChildEndIterator(); ++it) { recursiveRender(*it); } for(std::vector<AguiWidget*>::const_iterator it = root->getChildBeginIterator(); it != root->getChildEndIterator(); ++it) { recursiveRender(*it); } } else { nonConstRoot->paint(AguiPaintEventArgs(false,graphicsContext)); for(std::vector<AguiWidget*>::const_iterator it = root->getPrivateChildBeginIterator(); it != root->getPrivateChildEndIterator(); ++it) { recursiveRenderDisabled(*it); } for(std::vector<AguiWidget*>::const_iterator it = root->getChildBeginIterator(); it != root->getChildEndIterator(); ++it) { recursiveRenderDisabled(*it); } } //release clipping rectangle if(nonConstRoot->isClippingChildren()) { graphicsContext->popClippingRect(); } } I could ofcourse go to the top of the tree, then apply clipping rectangles inward until I get to the currently rendered widget, but that would involve lots of clipping rectangles @ 60 frames per second. I want to minimize calls to pushing and popping rectangles. What could I do, Thanks

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• Trouble creating a Java policy server for a simple Flash app

  - by simonwulf

  I'm trying to create a simple Flash chat application for educational purposes, but I'm stuck trying to send a policy file from my Java server to the Flash app (after several hours of googling with little luck). The policy file request reaches the server that sends a harcoded policy xml back to the app, but the Flash app doesn't seem to react to it at all until it gives me a security sandbox error. I'm loading the policy file using the following code in the client: Security.loadPolicyFile("xmlsocket://myhostname:" + PORT); The server recognizes the request as "<policy-file-request/" and responds by sending the following xml string to the client: public static final String POLICY_XML = "<?xml version=\"1.0\"?>" + "<cross-domain-policy>" + "<allow-access-from domain=\"*\" to-ports=\"*\" />" + "</cross-domain-policy>"; The code used to send it looks like this: try { _dataOut.write(PolicyServer.POLICY_XML + (char)0x00); _dataOut.flush(); System.out.println("Policy sent to client: " + PolicyServer.POLICY_XML); } catch (Exception e) { trace(e); } Did I mess something up with the xml or is there something else I might have overlooked?

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• Java File IO Compendium

  - by Warren Taylor

  I've worked in and around Java for nigh on a decade, but have managed to ever avoid doing serious work with files. Mostly I've written database driven applications, but occasionally, even those require some file io. Since I do it so rarely, I end up googling around for quite some time to figure out the exact incantation that Java requires to read a file into a byte[], char[], String or whatever I need at the time. For a 'once and for all' list, I'd like to see all of the usual ways to get data from a file into Java, or vice versa. There will be a fair bit of overlap, but the point is to define all of the subtle different variants that are out there. For example: Read/Write a text file from/to a single String. Read a text file line by line. Read/Write a binary file from/to a single byte[]. Read a binary file into a byte[] of size x, one chunk at a time. The goal is to show concise ways to do each of these. Samples do not need to handle missing files or other errors, as that is generally domain specific. Feel free to suggest more IO tasks that are somewhat common and I have neglected to mention.

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• Operator issues with cout

  - by BSchlinker

  I have a simple package class which is overloaded so I can output package data simply with cout << packagename. I also have two data types, name which is a string and shipping cost with a double. protected: string name; string address; double weight; double shippingcost; ostream &operator<<( ostream &output, const Package &package ) { output << "Package Information ---------------"; output << "Recipient: " << package.name << endl; output << "Shipping Cost (including any applicable fees): " << package.shippingcost; The problem is occurring with the 4th line (output << "Recipient:...). I'm receiving the error "no operator "<<" matches these operands". However, line 5 is fine. I'm guessing this has to do with the data type being a string for the package name. Any ideas?

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• PIC C - USB_CDC_GETC() and retrieving strings.

  - by Adam

  Hi all, I'm programming a PIC18F4455 Microcontroller using PIC C. I'm using the USB_CDC.h header file. I have a program on the computer sending a string such as "W250025". However, when I use usb_cdc_getc() to get the first char, it freezes. Sometimes the program sends only 'T', so I really want to just get the first character. Why does my code never execute past received=usb_cdc_getc(); when I send "W250025"? if (usb_cdc_kbhit()) { //printf(lcd_putc, "Check 3"); delay_ms(3000); printf(lcd_putc, "\f"); received = usb_cdc_getc(); printf(lcd_putc, "Received "); lcd_putc(received); delay_ms(3000); printf(lcd_putc, "\f"); if (received == 'W'){ //waveform disable_interrupts(INT_TIMER1); set_adc_channel(0); load_and_print_array(read_into_int(), read_into_int());} else if (received == 'T'){ //temperature set_adc_channel(1); enable_interrupts(INT_TIMER1);} }

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• I'm having trouble with using std::stack to retrieve the values from a recursive function.

  - by Peter Stewart

  Thanks to the help I received in this post: http://stackoverflow.com/questions/2761918/how-do-i-use-this-in-a-member-function I have a nice, concise recursive function to traverse a tree in postfix order: void Node::postfix() { if (left != __nullptr) { left->postfix(); } if (right != __nullptr) { right->postfix(); } cout<<cargo<<"\n"; return; }; Now I need to evaluate the values and operators as they are returned. My problem is how to retrieve them. I tried the std::stack: #include <stack> stack <char*> s; void Node::postfix() { if (left != __nullptr) { left->postfix(); } if (right != __nullptr) { right->postfix(); } s.push(cargo); return; }; but when I tried to access it in main() while (!s.empty()) { cout<<s.top<<"\n"; s.pop; } I got the error: 'std::stack<_Ty::top': function call missing argument list; use '&std::stack<_Ty::top' to create a pointer to member' I'm stuck. Another question to follow shortly.

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• objective-c 2.0 properties and 'retain'

  - by Adam

  Stupid question, but why do we need to use 'retain' when declaring a property? Doesn't it get retained anyway when it's assigned something? Looking at this example, it seems that an object is automatically retained when alloc'ed, so what's the point? #import "Fraction.h" #import <stdio.h> int main( int argc, const char *argv[] ) { Fraction *frac1 = [[Fraction alloc] init]; Fraction *frac2 = [[Fraction alloc] init]; // print current counts printf( "Fraction 1 retain count: %i\n", [frac1 retainCount] ); printf( "Fraction 2 retain count: %i\n", [frac2 retainCount] ); // increment them [frac1 retain]; // 2 [frac1 retain]; // 3 [frac2 retain]; // 2 // print current counts printf( "Fraction 1 retain count: %i\n", [frac1 retainCount] ); printf( "Fraction 2 retain count: %i\n", [frac2 retainCount] ); // decrement [frac1 release]; // 2 [frac2 release]; // 1 // print current counts printf( "Fraction 1 retain count: %i\n", [frac1 retainCount] ); printf( "Fraction 2 retain count: %i\n", [frac2 retainCount] ); // release them until they dealloc themselves [frac1 release]; // 1 [frac1 release]; // 0 [frac2 release]; // 0 ¦output Fraction 1 retain count: 1 Fraction 2 retain count: 1 Fraction 1 retain count: 3 Fraction 2 retain count: 2 Fraction 1 retain count: 2 Fraction 2 retain count: 1 Deallocing fraction Deallocing fraction This is driving me crazy!

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• Creating and using a static lib in xcode (MacOSX)

  - by Alasdair Morrison

  I am trying to create a static library in xcode and link to that static library from another program. So as a test i have created a BSD static C library project and just added the following code: //Test.h int testFunction(); //Test.cpp #include "Test.h" int testFunction() { return 12; } This compiles fine and create a .a file (libTest.a). Now i want to use it in another program so I create a new xcode project (cocoa application) Have the following code: //main.cpp #include <iostream> #include "Testlib.h" int main (int argc, char * const argv[]) { // insert code here... std::cout << "Result:\n" <<testFunction(); return 0; } //Testlib.h extern int testFunction(); I right clicked on the project - add - existing framework - add other Selected the .a file and it added it into the project view. I always get this linker error: Build TestUselibrary of project TestUselibrary with configuration Debug Ld build/Debug/TestUselibrary normal x86_64 cd /Users/myname/location/TestUselibrary setenv MACOSX_DEPLOYMENT_TARGET 10.6 /Developer/usr/bin/g++-4.2 -arch x86_64 -isysroot /Developer/SDKs/MacOSX10.6.sdk -L/Users/myname/location/TestUselibrary/build/Debug -L/Users/myname/location/TestUselibrary/../Test/build/Debug -F/Users/myname/location/TestUselibrary/build/Debug -filelist /Users/myname/location/TestUselibrary/build/TestUselibrary.build/Debug/TestUselibrary.build/Objects-normal/x86_64/TestUselibrary.LinkFileList -mmacosx-version-min=10.6 -lTest -o /Users/myname/location/TestUselibrary/build/Debug/TestUselibrary Undefined symbols: "testFunction()", referenced from: _main in main.o ld: symbol(s) not found collect2: ld returned 1 exit status I am new to macosx development and fairly new to c++. I am probably missing something fairly obvious, all my experience comes from creating dlls on the windows platform. I really appreciate any help.

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• How to get rid of void-pointers.

  - by Patrick

  I inherited a big application that was originally written in C (but in the mean time a lot of C++ was also added to it). Because of historical reasons, the application contains a lot of void-pointers. Before you start to choke, let me explain why this was done. The application contains many different data structures, but they are stored in 'generic' containers. Nowadays I would use templated STL containers for it, or I would give all data structures a common base class, so that the container can store pointers to the base class, but in the [good?] old C days, the only solution was to cast the struct-pointer to a void-pointer. Additionally, there is a lot of code that works on these void-pointers, and uses very strange C constructions to emulate polymorphism in C. I am now reworking the application, and trying to get rid of the void-pointers. Adding a common base-class to all the data structures isn't that hard (few days of work), but the problem is that the code is full of constructions like shown below. This is an example of how data is stored: void storeData (int datatype, void *data); // function prototype ... Customer *myCustomer = ...; storeData (TYPE_CUSTOMER, myCustomer); This is an example of how data is fetched again: Customer *myCustomer = (Customer *) fetchData (int datatype, char *key); I actually want to replace all the void-pointers with some smart-pointer (reference-counted), but I can't find a trick to automate (or at least) help me to get rid of all the casts to and from void-pointers. Any tips on how to find, replace, or interact in any possible way with these conversions?

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