computer pong padde

I have a game development question, I am unsure of where to post. I am working on a pong game. I am trying to make a pong paddle go up and down and up the screen on its own. here is the code I am working on.


	computer_move = y;

	if(computer_move > screen_height)
	{
		computer_move=screen_height;
	}

	if(computer_move < -screen_height)
	{
		computer_move=-screen_height;
	}

I am able to get the paddle to be unbeatable.