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Diffstat (limited to 'Lib/turtledemo/minimal_hanoi.py')
-rw-r--r-- | Lib/turtledemo/minimal_hanoi.py | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/Lib/turtledemo/minimal_hanoi.py b/Lib/turtledemo/minimal_hanoi.py new file mode 100644 index 0000000..cfb78dc --- /dev/null +++ b/Lib/turtledemo/minimal_hanoi.py @@ -0,0 +1,76 @@ +#!/usr/bin/env python3 +""" turtle-example-suite: + + tdemo_minimal_hanoi.py + +A minimal 'Towers of Hanoi' animation: +A tower of 6 discs is transferred from the +left to the right peg. + +An imho quite elegant and concise +implementation using a tower class, which +is derived from the built-in type list. + +Discs are turtles with shape "square", but +stretched to rectangles by shapesize() + --------------------------------------- + To exit press STOP button + --------------------------------------- +""" +from turtle import * + +class Disc(Turtle): + def __init__(self, n): + Turtle.__init__(self, shape="square", visible=False) + self.pu() + self.shapesize(1.5, n*1.5, 2) # square-->rectangle + self.fillcolor(n/6., 0, 1-n/6.) + self.st() + +class Tower(list): + "Hanoi tower, a subclass of built-in type list" + def __init__(self, x): + "create an empty tower. x is x-position of peg" + self.x = x + def push(self, d): + d.setx(self.x) + d.sety(-150+34*len(self)) + self.append(d) + def pop(self): + d = list.pop(self) + d.sety(150) + return d + +def hanoi(n, from_, with_, to_): + if n > 0: + hanoi(n-1, from_, to_, with_) + to_.push(from_.pop()) + hanoi(n-1, with_, from_, to_) + +def play(): + onkey(None,"space") + clear() + hanoi(6, t1, t2, t3) + write("press STOP button to exit", + align="center", font=("Courier", 16, "bold")) + +def main(): + global t1, t2, t3 + ht(); penup(); goto(0, -225) # writer turtle + t1 = Tower(-250) + t2 = Tower(0) + t3 = Tower(250) + # make tower of 6 discs + for i in range(6,0,-1): + t1.push(Disc(i)) + # prepare spartanic user interface ;-) + write("press spacebar to start game", + align="center", font=("Courier", 16, "bold")) + onkey(play, "space") + listen() + return "EVENTLOOP" + +if __name__=="__main__": + msg = main() + print(msg) + mainloop() |