Conversation so far:
what is the use of include in c++
#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program.
what kind of c/c++ files can use the #include directive
One type of file that can be included using #include are Header File or Standard files.

Question: what does the file do
Self-contained rewrite: what does the header file or standard files do