Chapter 9, Problem 6PE

Program Plan Intro

Simulates the tennis game

Program Plan:

• Import the header file.
• Define the “main” method.
  • Call the “printIntro ()” method
  • Call the “getInputs ()” method.
  • Call the “simNMatches ()” method.
  • Call the “printSummary ()” method.
• Define the “printIntro()” method.
  • Print the intro statements.
• Define the “getInputs()” method.
  • Get the player A possible for win from the user.
  • Calculate the “probA” and “probB” values.
  • Get how many games to simulate from the user.
• Define the “simNMatches()” method.
  • Set the values
  • Iterate “i” until it reaches “n” value
    • Call the methods
    • Check “matchA” is greater than “matchB”
      • Increment the “winsA” value
    • Otherwise, increment the “winsB” value.
    • Return the values.
• Define the “simOneMatch ()” method
  • Set the values
  • Check the condition.
    • Call the “simOneGame ()” method.
    • Check “setA” is greater than “setB”
      • Increment the “matchA” value
    • Otherwise, increment the “matchB” value
    • Return the results
• Define the “matchOver ()” method
  • Check “a” or “b” is greater than 3
    • Return true
      • • Otherwise, return false.
• Define the “simOneSet ()” method
  • Call the method
  • Set the values
  • Check the condition.
    • Check “scoreA” is greater than “scoreB”
      • Increment the “setA” value
    • Otherwise, increment the “setB” value
      • • Return the results
• Define the “setOver ()” method
  • Check “a” or “b” is equal to 7
    • Return true
      • • Check “a” or “b” is greater than or equal to 6
        • • Check “a-b” is greater than or equal to 2
            • Return true
          • Otherwise, return false
        • Otherwise, return false.
• Define the “simOneGame ()” method
  • Set the values
  • Check the condition
    • Check “random ()” is less than “probA”
      • Increment the “scoreA” value
        • • Otherwise, increment the “scoreB” value
        • Return the results.
• Define the “gameOver ()” method
  • Check “a” or “b” is greater than or equal to 4
    • Check “a-b” is greater than or equal to 2
      • Return true
        • • Otherwise, return false
        • Otherwise, return false.
• Define the “printSummary ()” method
  • Display the results.
• Call the main method.

Program Description Answer

The program is to simulate a game of tennis.

Explanation of Solution

Program:

#import the header file

from random import random

#definition of main method

def main():

    #call the method

    printIntro()

    #call the method and store it in the variables

    probA, probB, n = getInputs()

    #call the method and store it in the variables

    winsA, winsB = simNMatches(n, probA, probB)

    #call the method

    printSummary(winsA, winsB, n)

#definition of "printIntro" method

def printIntro():

    #display the statements

    print("This program simulates a series of tennis matches between player")

    print('"A" and player "B". The abilities of each player are')

    print("represented by percentage chance of winning a volley. The")

    print("percentages add up to 100.")

    print()

    print("Game")

    print("As in real tennis, each game is played through 4 points")

    print("(Love, 15, 30, 40, game) where the player must win by two.")

    print("Players can score on either serve.")

    print()

    print("Set")

    print("A set is won when a player reaches 6 victorious games, and has a")

    print("lead of two. If for example, sets reach 6-5, the players will play")

    print("another round. If the score reaches 6-6, there will be a")

    print("tiebreaking game.")

    print()

    print("Match")

    print("A Match is won when a player reaches his/her 3rd victorious set.")

    print("No winning by two, no tie-breaker, for the purposes of this simulation")

    print()

#definition of "getInputs" method

def getInputs():

    #get the player A wins a serve

    probA = eval(input("What is the percent prob. player A wins a volley? "))

    #calculate the values

    probA = probA / 100

    probB = 1 - probA

    #get the input from the user

    n = eval(input("How many games to simulate? "))

    return probA, probB, n

#definition of "simNMatches" method

def simNMatches(n, probA, probB):

    #set the values

    winsA = winsB = 0

    #iterate until "n" value

    for i in range(n):

        #call the method and store it in the variables

        matchA, matchB = simOneMatch(probA, probB)

        #check "matchA" is greater than "matchB"

        if matchA > matchB:

            #increment the value

            winsA = winsA + 1

        #otherwise      

        else:

            #increment the value

            winsB = winsB + 1

    #return the results

    return winsA, winsB

#definition of "simOneMatch" method

def simOneMatch(probA, probB):

    #set the values

    matchA = matchB = 0

    #check the condition

    while not matchOver(matchA, matchB):

        #call the method and store it in the variables

        setA, setB = simOneSet(probA, probB)

        #check "setA" is greater than "setB"

        if setA > setB:

            #increment the value

            matchA = matchA + 1

        #otherwise

        else:

            #increment the value

            matchB = matchB + 1

    #return the results

    return matchA, matchB

#definition of "matchOver" method

def matchOver(a, b):

    #check "a" or "b" is greater than 3

    if a > 3 or b > 3:

        #return the result

        return True

    else:

        #return the result

        return False

#definition of "simOneSet" method

def simOneSet(probA, probB):

    #call the method and store it in the variables

    scoreA, scoreB = simOneGame(probA, probB)

    #set the values

    setA = setB = 0

    #check the condition

    while not setOver(setA, setB):

        #check "scoreA" is greater than "scoreB"

        if scoreA > scoreB:

            #increment the value

            setA = setA + 1

        else:

            #increment the value

            setB = setB + 1

    #return the results

    return setA, setB

#definition of "setOver" method

def setOver(a, b):

    #check "a" and "b" is equal to 7

    if a == 7 or b == 7:

        #return the result

        return True

    #check "a" or "b" is greater than or equal to 6

    elif a >= 6 or b >= 6:

        #check "a - b" is greater than or equal to 2

        if abs(a-b) >=2:

            #return the result

            return True

        else:

            #return the result

            return False

    else:

        #return the result

        return False

#definition of "simOneGame" method

def simOneGame(probA, probB):

    #set the values

    scoreA = scoreB = 0

    #check the condition

    while not gameOver(scoreA, scoreB):

        #check "random()" is less than "probA"

        if random() < probA:

            #increment the value

            scoreA = scoreA + 1

        else:

            #increment the value

            scoreB = scoreB + 1

    #return the result

    return scoreA, scoreB

#definition of "gameOver" method

def gameOver(a, b):

    #check "a" or "b" is greater than or equal to 4

    if a >= 4 or b >= 4:

        #check "a - b" is greater than or equal to 2

        if abs(a-b) >=2:

            #return the result

            return True

        else:

            #return the result

            return False

    else:

        #return the result

        return False

#definition of "printSummary" method

def printSummary(winsA, winsB, n):

    #display the results

    print("\nGames simulated: ", 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))

#call the main method

if __name__ == '__main__': main()

Sample Output

Output:

This program simulates a series of tennis matches between player

"A" and player "B". The abilities of each player are

represented by percentage chance of winning a volley. The

percentages add up to 100.

Game

As in real tennis, each game is played through 4 points

(Love, 15, 30, 40, game) where the player must win by two.

Players can score on either serve.

Set

A set is won when a player reaches 6 victorious games, and has a

lead of two. If for example, sets reach 6-5, the players will play

another round. If the score reaches 6-6, there will be a

tiebreaking game.

Match

A Match is won when a player reaches his/her 3rd victorious set.

No winning by two, no tie-breaker, for the purposes of this simulation

What is the percent prob. player A wins a volley? 50

How many games to simulate? 10

Games simulated:  10

Wins for A: 7 (70.0%)

Wins for B: 3 (30.0%)