Do you mean to say, you want to be able to launch your program from wherever, and inside the program use a command line program, such as ipconfig or copy, or do you want to be able to be on the command line and type your program and have it execute?
For the first one
1 2 3 4 5
//...
#include <windows.h>
//...
system("copy C:\\file.txt file2.txt") //note the double backslash, because the first one is an escape, the second one is saying you want the backslash
//..