Answers for "how to make a header file in c++"

what is a header in c++

// my_class.h
#ifndef MY_CLASS_H // include guard
#define MY_CLASS_H

namespace N
{
    class my_class
    {
    public:
        void do_something();
    };
}

#endif /* MY_CLASS_H */

what is a header in c++

// my_class.cpp
#include "my_class.h" // header in local directory
#include <iostream> // header in standard library

using namespace N;
using namespace std;

void my_class::do_something()
{
    cout << "Doing something!" << endl;
}

how does header files work in c++

"It works by copying your entire header file into the file specifying"
"a #include. It then compiles your code after this copy and pasting."

how to declare a function in c++ header file

//somefile.h
#ifndef SOMEFILE_H
#define SOMEFILE_H
int add(int a, int b);
#endif