Initializing Function Parameters (P.302)

1. Modify your TETRIS program so that when the function draw_block(i) and erase_block(i) are invoked without specifying the x and y coordinates, the default values would be x=0 and y=0.
2. Add a segment of code in your main program (before the loop which shows the falling down blocks) to test it.

   
   for (i=1; i<=7; i++)
       {
           draw_block(i);
           refresh();
           usleep(1000000);
           erase_block(i);
       }