In this code what is the role of the symbol "%3d"? I know that % means refer to a variable. This is the code: #include <stdio.h> int main(void) { int t, i, num[3][4]; for(t=0; t<3; ++t) for(i=0; i<4; ++i) num[t][i] = (t*4)+i+1; /* now print them out */ for(t=0; t<3; ++t) { for(i=0; i<4; ++i) ...
Hi, In C++, there is a fwrite() which writes a buffer to a file on disk: http://www.cplusplus.com/reference/clibrary/cstdio/fwrite/ Can you please tell me if there is any buffer inside that fwrite implementation? i.e. if I call fwrite() multiple times (say 10 times), does it actually invoke file i/o 10 different times? I am asking t...
Greetings, I am trying to figure out which C/C++ compiler to use. I found this list of C/C++ compilers at Wikipedia: http://en.wikipedia.org/wiki/List_of_compilers#C.2FC.2B.2B_compilers I am fairly certain that I want to go with an open source compiler. I feel that if it is open source then it will be a more complete compiler since ma...
What is the role of the #define directive? ...
I am writing a test program to understand vector's better. In one of the scenarios, I am trying to insert a value into the vector at a specified position. The code compiles clean. However, on execution, it is throwing a Segmentation Fault from the v8.insert(..) line (see code below). I am confused. Can somebody point me to what is wrong ...
Hi I am working on a program where I have to initialize a deck of cards. I am using a struct to represent a card. However I'm not filling it correctly as I get a bunch of zero's when I display the deck of cards. I believe my mistake is in this line but I'm not sure: struct card temp = {"Clubs", value, false}; The code: void initCard...
What is the purpose of the following esoteric C++ operators? Pointer to member ::* Bind pointer to member by pointer ->* Bind pointer to member by reference .* (reference) ...
I'm dealing with a problem which needs to work with a lot of data. Currently its values are represented as an unsigned int. I know that real values do not exceed a limit of 1000. Questions I can use unsigned short to store it. An upside to this is that it'll use less storage space to store the value. Will performance suffer? If I dec...
I have a Visual Studio 2008 Windows Mobile 6 C++ application that is using an API that requires the use of LocalAlloc(). To make my life easier, I created an implementation of a standard allocator that uses LocalAlloc() internally: /// Standard library allocator implementation using LocalAlloc and LocalReAlloc /// to create a dynamical...
I have a table with an auto-incrementing ID. After inserting a new row, I would like to retrieve the new ID. I found an article that used the MySQL function LAST_INSERT_ID(). The article says to create a new query and submit it. I'm using MySQL Connector C++, Windows XP and Vista, and Visual Studio 9. Here are my questions: Is ...
Sorry if this has been asked. Just like I can select in C# project that I want it to build for .NET 2.0 runtime, is it possible for native c++ project to be built against older CRT, let's say one from visual studio 2005? I would like this because I have external SDK that was build with VS2005, but I'd like to use newer IDE. ...
please see comments inline bool res = false; DWORD dwNeeded = DocumentPropertiesW(NULL, m_currPrinterHandle, (LPWSTR) m_currPrinterName.c_str(), NULL, NULL, 0); if (m_devmode_buf) { GlobalFree(m_devmode_buf); } m_devmode_buf = GlobalAlloc(GPTR, dwNeeded); GetLastError(); // = 0; if (m_devmode_buf) { LPDEVMODEW devmode_buf...
I'm trying to build a basic POP3 mail client in C/++, but I've run into a bit of an issue. Since you have to define the buffer size when building the program, but a message can be arbitrarily large, how do you, say, get the mail server to send it to you in parts? And if this isn't the correct means of solving the problem, what is? And w...
So I am a first year computer science student, for on of my final projects, I need to write a program that takes a vector of strings, and applies various functions to these. Unfortunately, I am really confused on how to use pointer to pass the vector from function to function. Below is some sample code to give an idea of what I am talk...
The following code raises a runtime error: #include <iostream> #include <iterator> #include <ext/slist> class IntList : public __gnu_cxx::slist<int> { public: IntList() { tail_ = begin(); } // seems that there is a problem here void append(const int node) { tail_ = insert_after(tail_, node); } private: iterator tail_; }; ...
I have 2 structures that have 90% of their fields the same. I want to group those fields in a structure but I do not want to use the dot operator to access them. The reason is I already coded with the first structure and have just created the second one. before: typedef struct{ int a; int b; int c; object1 name; } str1; ...
I'm trying to derive a new class from an old one. The base class declaration looks like this: class Driver : public Plugin, public CmdObject { protected: Driver(); public: static Driver* GetInstance(); virtual Engine& GetEngine(); public: // Plugin methods... virtual bool InitPlugin (Mgr* pMgr); virtual bool Ope...
you have a class A, where you set ctor to be private, so a client can't call "A a;" to create obj on stack. But someday another developer add a new ctor: "A(int)" and try to call "A a(1);" inside main(). So this will create a obj on stack. How do you prevent that? ...
Every so often, in MSVC 2005/8, the erratic Intellisense would randomly decide to kick in and do something wondrous: auto-complete the ENTIRE declaration at once, while having laboriously been re-typing/selecting the function definition for the 1000th time. No, I wasn't drunk at the time. But I did see it happen occasionally--maybe 10 to...
So, I have a project that must add, delete, and print the contents of a vector... the problem is that, when run the program exits before I can type in the string to add to the vector. I commented the function that that portion is in. Thanks! #include <iostream> #include <cstdlib> #include <vector> #include <string> using namespace std...