class Ball { float posX; float posY; float speedX; float speedY; void move(){ posX += speedX; posY += speedY; if ( posX > width-15 ){ posX = width - 15; speedX = -speedX; } if( posX < 15 ){ posX = 15; speedX = -speedX; } if( posY > height-15){ posY = height - 15; speedY = -speedY; } if( posY - 15 < 0 ){ posY = 15; speedY = -speedY; } } }