make bouncing turtle with python
Question: i am a beginner with python I wrote this code to make bouncing ball with
turtle it works but have some erors like ball dissapering

    
    
    import turtle
    turtle.shape("circle")
    xdir = 1
    x = 1
    y = 1
    ydir = 1
    while True:
         x = x + 3 * xdir
         y = y + 3 * ydir
        turtle.goto(x , y)
        if x >= turtle.window_width():
            xdir = -1
        if x <= -turtle.window_width():
            xdir = 1
        if y >= turtle.window_height():
            ydir = -1
        if y <= -turtle.window_height():
            ydir = 1
        turtle.penup()
    turtle.mainloop()
    


Answer: You need `window_width()/2` and `window_height()/2` to keep inside window.

ie.

    
    
    if x >= turtle.window_width()/2:
        xdir = -1
    if x <= -turtle.window_width()/2:
        xdir = 1
    if y >= turtle.window_height()/2:
        ydir = -1
    if y <= -turtle.window_height()/2:
        ydir = 1
    

