It allows the differentiation of bitwise const and logical const. Logical const is when an object doesn’t change in a way that is visible through the public interface, like your locking example. Another example would be a class that computes a value the first time it is requested, and caches the result. Since c++11 mutable … Read more
Just to clarify something that came up in some of the other answers… There is no requirement that the initializer list be in either the source (.cpp) or header (.h) file. In fact, the compiler does not distinguish between the two types of files. The important distinction is between the contructor’s declaration and it’s definition. … Read more
It depends on the order of data member declarations in the class. So a_ will be the first one, then b_ will be the second one in your example.
Assuming what you need is a simple byte swap, try something like Unsigned 16 bit conversion: swapped = (num>>8) | (num<<8); Unsigned 32-bit conversion: swapped = ((num>>24)&0xff) | // move byte 3 to byte 0 ((num<<8)&0xff0000) | // move byte 1 to byte 2 ((num>>8)&0xff00) | // move byte 2 to byte 1 ((num<<24)&0xff000000); // … Read more
1. Primary Class Template When you write has_member<A>::value, the compiler looks up the name has_member and finds the primary class template, that is, this declaration: template< class , class = void > struct has_member; (In the OP, that’s written as a definition.) The template argument list <A> is compared to the template parameter list of … Read more
I have verified a solution here using Visual Studio 2010. Via this MSDN article and MSDN blog post. The trick is an obscure call to _setmode(…, _O_U16TEXT). Solution: #include <iostream> #include <io.h> #include <fcntl.h> int wmain(int argc, wchar_t* argv[]) { _setmode(_fileno(stdout), _O_U16TEXT); std::wcout << L”Testing unicode — English — Ελληνικά — Español.” << std::endl; } … Read more
When you add the const keyword to a method the this pointer will essentially become a pointer to const object, and you cannot therefore change any member data. (Unless you use mutable, more on that later). The const keyword is part of the functions signature which means that you can implement two similar methods, one … Read more
C++11 introduces std::stoi (and variants for each numeric type) and std::to_string, the counterparts of the C atoi and itoa but expressed in term of std::string. #include <string> std::string s = std::to_string(42); is therefore the shortest way I can think of. You can even omit naming the type, using the auto keyword: auto s = std::to_string(42); … Read more
The program will not work properly because at Line 1, when the user presses Enter, it will leave in the input buffer 2 character: Enter key (ASCII code 13) and \n (ASCII code 10). Therefore, at Line 2, it will read the \n and will not wait for the user to enter a character. The … Read more
For POD data members, it makes no difference, it’s just a matter of style. For class members which are classes, then it avoids an unnecessary call to a default constructor. Consider: class A { public: A() { x = 0; } A(int x_) { x = x_; } int x; }; class B { public: … Read more