Applying the update method for prototyping gameplay

The update method is all about abstraction. Let’s learn through an example. Imagine building a Pong clone with only rudimentary knowledge of C++. It might look something like this:

Naïve Pong code

Entity aiPaddle;
Entity ball;
Vector2D direction;
// Main game loop
while (looping)
{
    Vector2D ballPos = ball.GetPosition();
    ballPos += direction;
    ball.SetPosition(ballPos);
    if (ballPos.y > aiPaddle.GetPosition().y)
    {
        aiPaddle.MoveUp();
    }
    else
    {
        aiPaddle.MoveDown();
    }
    // Input, collisions, and rendering...
}

This code may work for Pong but the problem is pretty clear. As you add more and...