I was curious about this so I wrote the following test program and compiled it with g++ version 4.1.2. include <iostream> #include <string> using namespace std; class test { public: test(const char *name) : _name(name) { cout << _name << ” created” << endl; } ~test() { cout << _name << ” destroyed” << endl; … Read more
The direct answer is that yes, that’s okay. A lot of people have thrown around various ideas of how to improve speed, but there seems to be quite a bit of disagreement over which is most effective. I decided to write a quick test program to get at least some idea of which techniques did … Read more
A proxy is a class that provides a modified interface to another class. Here is an example – suppose we have an array class that we only want to contain binary digits (1 or 0). Here is a first try: struct array1 { int mArray[10]; int & operator[](int i) { /// what to put here … Read more
Excuse me when I answer your questions out-of-order, it makes it easier to understand this way. When static variable is declared in a header file is its scope limited to .h file or across all units. There is no such thing as a “header file scope”. The header file gets included into source files. The … Read more
While it won’t reveal unneeded include files, Visual studio has a setting /showIncludes (right click on a .cpp file, Properties->C/C++->Advanced) that will output a tree of all included files at compile time. This can help in identifying files that shouldn’t need to be included. You can also take a look at the pimpl idiom to … Read more
Straightforward way: char digits[] = {‘0’, ‘1’, ‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’ }; char aChar = digits[i]; Safer way: char aChar=”0″ + i; Generic way: itoa(i, …) Handy way: sprintf(myString, “%d”, i) C++ way: (taken from Dave18 answer) std::ostringstream oss; oss << 6; Boss way: Joe, write me an int to char … Read more
You don’t have to write a completely new container class. You can stick with your STL containers, but change the second parameter of for example std::vector to give it your custom allocator which allocates from a stack-buffer. The chromium authors wrote an allocator just for this: https://chromium.googlesource.com/chromium/chromium/+/master/base/stack_container.h It works by allocating a buffer where you … Read more
I’ve worked out a perfectly manageable answer. How clean you’d like this to be is entirely based upon how much work you’re willing to do. First, take your C++ class and create C “wrapper” functions to interface with it. For example, if we have this C++ class: class MBR { std::string filename; public: MBR (std::string … Read more
No. Here are several examples why: Template code is impossible to write with exception specifications, template<class T> void f( T k ) { T x( k ); x.x(); } The copies might throw, the parameter passing might throw, and x() might throw some unknown exception. Exception-specifications tend to prohibit extensibility. virtual void open() throw( FileNotFound … Read more
If you put the declaration in a header file, and the definition in a separate .cpp file, and #include the header from a different .cpp file, you will be able to see the difference. Specifically, suppose: lib.h int Add(int a, int b); lib.cpp int Add(int a, int b = 3) { … } test.cpp #include … Read more