OH! Thanks !!! Now I have another one.

Its in this code:

function update_paddle(var paddle_pos,var paddle_mode,var key)
{
if (COMPUTER == paddle_mode)
{
if ((ponged_ball.pos_x > 10) && (ponged_ball.pos_x < 600)) // Gives computer boundries.
*paddle_pos = ponged_ball.pos_y - 42;
}
else if (USER == paddle_mode)
{
*paddle_pos += 30*time_step*key;
*paddle_pos = clamp(*paddle_pos,35,470);
}

}

And the error is this:

Error in 'MAIN' line 143: illegal indirection

< "padde_pos = ponged_ball.pos_y - 42; >
.
Can't compile PING_PONG_TEST2.C