ok lets say I have my code file in my web server and any one can call that functions in that file ( assuming they know the name of the functions ) but they can't see the actual implementation
in other word they can use the implementation but they can't see it
Example: data.cpp in my server and it has a function called "move() " a friend want to use the function in his code by calling the function but he can't see the implementation of that function
How would that be possible ?