Or #include <windows.h> and do this:
ShellExecute(NULL, "open", "c:/path_to_exe/program.exe", NULL, "c:/path_to_execute_from/", SW_SHOWNORMAL);
You should use get_executable_name for the full path (3rd argument), and a combination of get_executable_name and replace_filename for the path to execute from (5th argument) to work as I expect you want it to. See kikabo's post for that.
You could also use WinExec("path", SW_SHOWNORMAL) if you do not need it to be executed from the path. I still recommend ShellExecute, though.