python——体育竞技

一、体育竞技分析
基本规则
两个球员，交替用球拍击球
发球权，回合
未能进行一次击打回合结束
首先达到15分赢得比赛

1、自顶向下的设计

 #7_game_2.py
 from random import * 

 def main():
     printIntro()#介绍程序信息
     probA,probB,n = getInputs()#输入参数
     winsA, winsB = simNGames(n,probA,probB)#获胜场数
     PrintSummary(winsA, winsB)

 def printIntro():
     print('This program simulates a game between two')
     print('There are two players, A and B')
     print('Probability(a number between 0 and 1)is used')

 def getInputs():
     a = eval(input('What is the prob.player A wins?'))#eval()将str转换为数字型
     b = eval(input('What is the prob.player B wins?'))
     n = eval(input('How many games to simulate?'))
     return a,b,n

 def simNGames(n,probA,probB):
     winsA = 0
     winsB = 0
     for i in range(n):
         scoreA,scoreB = simOneGame(probA,probB)#得分情况
         if scoreA >scoreB:
             winsA = winsA + 1
         else:
             winsB = winsB + 1
     return winsA,winsB
 def simOneGame(probA,probB):
     scoreA = 0
     scoreB = 0
     serving = "A"#开始循环的初始标志
     while not gameOver(scoreA,scoreB):
         if serving == "A":
             if random() < probA:
                 scoreA = scoreA + 1
             else:
                 serving = "B"
         else:
             if random() < probB:
                 scoreB = scoreB + 1
             else:
                 serving = "A"
     return scoreA,scoreB

 def gameOver(a,b):#循环结束的标志
     return a==15 or b==15

 def PrintSummary(winsA, winsB):
     n = winsA + winsB
     print('\nGames simulated:%d'%n)
     print('Wins for A:{0}({1:0.1%})'.format(winsA,winsA/n))
     print('Wins for B:{0}({1:0.1%})'.format(winsB,winsB/n))

 if __name__ == '__main__':
     main()

载入程序，对各个函数分别测试

整个过程反映了，由顶至下的设计和由下至上的运行，整个编程的思路就是这样。

（2）程序简化

 import random

 def onegame(probA,probB):
         scoreA=0
         scoreB=0
         mark="A"
         while mark=="A":
                 a=random.random()
                 b=random.random()
                 a=a*probA
                 b=b*probB
                 if a>b:
                         scoreA+=1
                 else:
                         scoreB+=1
                 if scoreA==15 or scoreB==15:
                         mark="B"
         return scoreA,scoreB

 def Ngame(n,probA,probB):
         numA=0
         numB=0
         for i in range(n):
                 scoreA,scoreB=onegame(probA,probB)
                 if scoreA>scoreB:
                         numA+=1
                 else:
                         numB+=1
         return numA,numB

 def main():
         probA=eval(input("probA is :"))
         probB=eval(input("probB is :"))
         n=eval(input("num is :"))

         numA,numB=Ngame(n,probA,probB)
         print('Games simulated:%d'%n)
         print('Wins for A:{0}({1:0.1%})'.format(numA,numA/n))
         print('Wins for B:{0}({1:0.1%})'.format(numB,numB/n))

 if __name__ == "__main__":
     main()