argc is the number of command line arguments to a program, INCLUDING the name
of the program itself.

In bash:

$ gcc  print_integer.c  test_print_integer.c  -o test_print_integer


Inside gcc:

    argc = 5

    argv[0] = "gcc"
    argv[1] = "print_integer.c"
    argv[2] = "test_print_integer.c"
    argv[3] = "-o"
    argv[4] = "test_print_integer"