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.
what does the header file or standard files do
Header File or Standard files contain C/C++ function declarations and macro definitions to be shared between several source files.
what kind of function declarations are contained in header file or standard files
Header File or Standard files contain functions like the printf(), scanf(), cout, cin and various other input-output or other standard functions.

Question: what is another type of file
Self-contained rewrite: what is another type of c/c++ file besides header file or standard files that can use the #include directive