from graphics import *

def main():
    window = GraphWin("stack diagram", 1500, 1000)
    directory = '/home/richardw/public_html/cs21-s14/stack'

    number = 0
    quit = False
    while not quit:
        filename = "%s/stack8.%02d.gif" % (directory, number)
        image = Image(Point(750,500), filename)
        image.draw(window)

        validKey = False
        while not validKey:
            key = window.getKey()
            if key == 'q':
                validKey = True
                quit = True
            elif key == 'Right':
                number = number + 1
                if number > 25:
                    number = 25
                else:
                    validKey = True
            elif key == 'Left':
                number = number - 1
                if number < 0:
                    number = 0
                else:
                    validKey = True
                    
        image.undraw()

    window.close()

main()