Continuing, we have
glutInitWindowSize( 400, 400 );
glutInitWindowPosition( 0, 0 );
glutCreateWindow( argv[0] );
The window will be 400×400 and located with it's upper-left corner at (0,0). Actually, these are only requests to the windowing system; it may choose not to honor them.
argv[0] is a string containing the name of the program. Any valid string could be used here.