習題 35: 分支和函數

你已經學會了 if 語句、函數、還有列表。現在你要練習扭轉一下思維了。把下面的代碼寫下來，看你是否能弄懂它實現的是什么功能。

from sys import exit

def gold_room():
    print "This room is full of gold.  How much do you take?"

    next = raw_input("> ")
    if "0" in next or "1" in next:
        how_much = int(next)
    else:
        dead("Man, learn to type a number.")

    if how_much < 50:
        print "Nice, you're not greedy, you win!"
        exit(0)
    else:
        dead("You greedy bastard!")


def bear_room():
    print "There is a bear here."
    print "The bear has a bunch of honey."
    print "The fat bear is in front of another door."
    print "How are you going to move the bear?"
    bear_moved = False

    while True:
        next = raw_input("> ")

        if next == "take honey":
            dead("The bear looks at you then slaps your face off.")
        elif next == "taunt bear" and not bear_moved:
            print "The bear has moved from the door. You can go through it now."
            bear_moved = True
        elif next == "taunt bear" and bear_moved:
            dead("The bear gets pissed off and chews your leg off.")
        elif next == "open door" and bear_moved:
            gold_room()
        else:
            print "I got no idea what that means."


def cthulhu_room():
    print "Here you see the great evil Cthulhu."
    print "He, it, whatever stares at you and you go insane."
    print "Do you flee for your life or eat your head?"

    next = raw_input("> ")

    if "flee" in next:
        start()
    elif "head" in next:
        dead("Well that was tasty!")
    else:
        cthulhu_room()


def dead(why):
    print why, "Good job!"
    exit(0)

def start():
    print "You are in a dark room."
    print "There is a door to your right and left."
    print "Which one do you take?"

    next = raw_input("> ")

    if next == "left":
        bear_room()
    elif next == "right":
        cthulhu_room()
    else:
        dead("You stumble around the room until you starve.")


start()

你應該看到的結果

下面是我玩游戲的過程：

$ python ex35.py
You are in a dark room.
There is a door to your right and left.
Which one do you take?
> left
There is a bear here.
The bear has a bunch of honey.
The fat bear is in front of another door.
How are you going to move the bear?
> taunt bear
The bear has moved from the door. You can go through it now.
> open door
This room is full of gold.  How much do you take?
> asf
Man, learn to type a number. Good job!
$

加分習題

1. 把這個游戲的地圖畫出來，把自己的路線也畫出來。
2. 改正你所有的錯誤，包括拼寫錯誤。
3. 為你不懂的函數寫注解。記得文檔注解該怎么寫嗎？
4. 為游戲添加更多元素。通過怎樣的方式可以簡化并且擴展游戲的功能呢？
5. 這個 gold_room 游戲使用了奇怪的方式讓你鍵入一個數字。這種方式會導致什么樣的 bug？ 你可以用比檢查 0、1 更好的方式判斷輸入是否是數字嗎？int() 這個函數可以給你一些頭緒。