146 CHAPTER9. SIMULATIONANDDESIGN

else: # A loses serve
serving = "B"
else:
if random() < probB: # B wins the serve
scoreB = scoreB+ 1
else: # B loses the serve
serving = "A"

Thatprettymuchcompletesthefunction.It gota bitcomplicated,butseemstoreflecttherulesofthe
simulationasthey werelaidout.Puttingthefunctiontogether, hereis theresult.

def simOneGame(probA, probB):
scoreA = 0
scoreB = 0
serving = "A"
while gameNotOver(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

9.3.6 FinishingUp

Whew!We have justonemoretroublesomefunctionleft,gameOver. Hereis whatweknow aboutit sofar.

def gameOver(a,b):

a and b representscores for a racquetball game

RETURNS trueif the game is over, false otherwise.

Accordingtotherulesforoursimulation,a gameis overwheneitherplayerreachesa totalof15.We can
checkthiswitha simpleBooleancondition.

def gameOver(a,b):

a and b representscores for a racquetball game

RETURNS trueif the game is over, false otherwise.

return a==15 or b==15

Noticehow thisfunctiondirectlycomputesandreturnstheBooleanresultallinonestep.
We’ve doneit!ExceptforprintSummary, theprogramis complete.Let’s fillinthemissingdetails
andcallit a wrap.Hereis thecompleteprogramfromstarttofinish:

rball.py

from random importrandom

def main():
printIntro()
probA, probB, n = getInputs()
winsA, winsB = simNGames(n,probA, probB)
printSummary(winsA,winsB)