Question

I always make a class called Constants in Java to store constant values which will be used in an application.

For all the classes of the application

class Constants {

    public static final int GOOD_RES = 1;
    public static final int BAD_RES = 0;
    public static final int FILE_NOT_READ = 10;
    // To be continued
}

or for a single class

class SomeClass {

    private static final int GOOD_RES = 1;
    private static final int BAD_RES = 0;
    private static final int FILE_NOT_READ = 10;
    // To be continued
}

How to do the same in C++? I can make a class in a header file with declarations and place definitions in a CPP file. For example.

Header file.

class const_values {
    const static int GOOD_STATE = 1;
    const static int BAD_STATE = 2;
    const static string s;
}

CPP file

string const_values::s = "lorem ipsum";

Is it OK?

Answer 1

Use namespace for that:

constants.h:

#include <string>
namespace Constants
{
    const int GOOD_STATE = 1;
    const int BAD_STATE = 2;
    const std::string str("test");
}

main.cpp:

#include <iostream>
#include "constants.h"
int main(int argc, char** argv)
{   
    std::cout << Constants::GOOD_STATE << " " << Constants::str << std::endl;
}

Output: 1 test