What is the difference between header (.h) and source (.cpp) files?

Question

I was just wondering what the difference between .cpp and .h files is? What would I use a header file (.h) for and what would I use a .cpp file for?

Answer 1

In general, and it really could be a lot less general:

.h (header) files are for declarations of things that are used many times, and are #included in other files

.cpp (implementation) files are for everything else, and are almost never #included