Create three files: my.h, my.cpp, and use.cpp. The header file my.h contains extern int foo; void print_foo(); void print(int); The source code file my.cpp #includes my.h and std_lib_facilities.h, defines print_foo() to print the value of foo using cout, and print(int i) to print the value of i using cout. The source code file use.cpp #includes my.h, defines main() to set the value of foo to 7 and print it us- ing print_foo(), and to print the value of 99 using print(). Note that use.cpp does not #include std_lib_facilities.h as it doesn't directly use any of those facilities. Get these files compiled and run. On Windows, you need to have both use.cpp and my.cpp in a project and use { char cc; cin>>cc; } in use.cpp to be able to see your output. Hint: You need to #include to use cin.