练习代码（2）

2.1

import easyguieasygui.msgbox("hello,world!")

2.2

import easygui as gimport syswhile 1:        g.msgbox("welcome")                msg =("Do you hunger for knowledge?")        title = "game"        choices =["coding","sleeping","reading","loving"]        choice = g.choicebox(msg,title,choices)        g.msgbox("Your choice is "+ str(choice),"result")        msg = "restart?"        title = "please have your choice"        if g.ccbox(msg.title):                pass        else:                sys.exit(0)

2.3

import random as rclass Fish:    def __init__(self):        self.x = r.randint(0,10)        self.y = r.randint(0,10)    def move(self):        self.x -= 1        print("my position is ",self.x,self.y)class A(Fish):    passclass B(Fish):    passclass C(Fish):    passclass D(Fish):    def __init__(self):##        Fish.__init__(self)        super().__init__()        self.hungry = True    def eat(self):        if self.hungry:            print("eat them all!")            self.hungry = False        else:            print("that's enough")

2.4

import time as tclass Mytimer():    def __init__(self):        self.prompt ="未开始计时"        self.lasted =[]        self.start =0        self.stop =0##    def __str__(self):##        return self.prompt        def start(self):        self.start = t.localtime()        print("开始计时")    def stop(self):        self.stop = t.localtime()        print("计时结束")    def calculate(self):        self.lasted =[]        self.prompt ="总共运行"        for index in range(6):            self.lasted.append(self.stop[index]-self.start[index])            self.prompt+= str(self.lasted[index])        print(self.prompt)

2.5

def sqrt(x):#判断完全平方数    ans=0    if x>=0:        while ans*ans<x:            ans+=1        if ans*ans!=x:            print(x," ia not a perfect squart")            return None        else: return ans    else:        print("x should be positive")        return Nonedef solve(legs,heads):    for chicks in range(0,heads+1):#进行循环        pigs=heads-chicks        tot=4*pigs+2*chicks        if tot==legs:#寻找到满足限制的条件            return(chicks,pigs)    return(None,None)def barnYard():    heads=int(input("enter the number of heads"))    legs=int(input("enter the number of legs"))    pigs,chicks=solve(legs,heads)    if pig == None:        print("no solution")    else:        print("number of pigs",pigs)        print("number of chicks",chicks)def solve1(legs,heads):    for spiders in range(0,heads+1):        for chicks in range(0,heads+1):            pigs=heads-chicks            tot=4*pigs+2*chicks+8*spiders            if tot==legs:                return(chicks,pigs,spiders)    return(None,None,None)def barnYard1():    heads=int(input("enter the number of heads"))    legs=int(input("enter the number of legs"))    pigs,chicks=solve1(legs,heads)    if pigs == None:        print("no solution")    else:        print("number of pigs",pigs)        print("number of chicks",chicks)        print("number of spiders",spiders)def solve2(legs,heads):    solutionFound = False    for spiders in range(0,heads+1):        for chicks in range(0,heads+1):            pigs=heads-chicks            tot=4*pigs+2*chicks+8*spiders            if tot==legs:                return(chicks,pigs,spiders)                print("number of pigs",pigs)                print("number of chicks",chicks)                print("number of spiders",spiders)            solutionFound=True    return(None,None,None)    if not solutionFound: print("no solution")

2.6

def isPalindrome(n):#字符串赋值到n，然后比较回文序列    if len(n)<=1: return True    else: return n[0]==n[-1] and isPalindrome(n[1:-1])def isPalindrome1(n,indent):    print(indent,"isPalindrome called with",n)    if len(n)<=1:        print(indent,"about to return True from base case")        return True    else:        ans=n[0]==n[-1]and isPalindrome1(n[1:-1],indent+indent)        print(indent,"about to return",ans)        print(ans)