Draw a blue filled triangle, then terminate

Listing 9 calls the triangle function to draw the filled blue triangle on the right in Figure 1.

Listing 9. Draw a blue filled triangle, then terminate. 
  triangle(screen,280,180,
                  320,180,
                  300,220,makecol(0,0,255));

  //Block and wait for the user
  // to press any key.
  readkey();

  return 0;
}//end main function
END_OF_MAIN();