CS 30 Homework 5

Due by class time Wednesday, March 8

If you wish, you may work with a partner on this assignment.

Reading

• Finish reading Chapters 7 and 8 of your Python textbook.

• Study the code examples from class from this week and last week.

Practice Exercises (Optional)

These problems are recommended if you feel the need for some extra programming practice using decisions and loops in Python, but they are not required.

• Question 2 on page 227. Trace through the code fragment by hand for each of the given inputs, and then verify your answers by running the code in Python.

• Exercise 6 on page 229.

• Exercise 7 on page 229.

• Exercise 8 on page 229.

• Write a program to simulate repeatedly rolling two dice until both come up with the same number. In addition to printing out the dice values, if the program rolls double ones it should print out "Snake eyes!" If double sixes are rolled, it should print out "Box cars!" Otherwise, it should just print out "Doubles!" For example, a sample run of the program might look like the following:

  We will simulate rolling two dice until we get doubles...
  5 3
  1 4
  2 6
  1 1
  Snake eyes! 
  

  To generate the dice rolls, you can use random.randrange(a, b) from the random module.

Problems to Turn In

1. Finish the exercises from Lab 6. Name your programs as follows:

   • Parts 1-4: piglatin, firstVowelPos, translateWord, translate

   • Part 5: bmi

   • Part 6 (Exercise 17 on page 230): bounce

   • Part 7: rps

2. Now modify your Rock-Paper-Scissors program so that, unknown to the user, the computer occasionally cheats by changing its own choice after the user has entered theirs. This should happen with a probability of 30%.

3. Write a program called craps that simulates the casino game of Craps, which is played as follows. You start by rolling two dice and looking at the total. The game then breaks down into the following cases based on that first roll:

   • You rolled a 2, 3, or 12. Rolling these totals on your first roll is called crapping out and means that you lose.
   • You rolled a 7 or 11. When either of these totals comes up on your first roll, it is called a natural, and you win.
   • You rolled one of the other totals (4, 5, 6, 8, 9, or 10). In this case, the value you rolled is called your point, and you continue to roll the dice until either you roll your point a second time, in which case you win, or you roll a 7, in which case you lose. If you roll any other value (including 2, 3, 11, and 12, which are no longer treated specially), you just keep on rolling until your point or a 7 appears.

Extra Credit

You should finish the other problems first before attempting these.

• Extend your craps program so that it simulates multiple games, keeping track of the number of games won, and then reports the estimated probability of winning. For example, if the player wins 249 out of 500 games, then the estimated probability of winning is 249/500 = 0.498.

• Do Exercise 2 on page 262. Call your program windchill.

• Do Exercises 12-14 on pages 293-294. Call your program randomwalk.

Turning in Your Homework

Put all of your code into a single file called assign5.py. Include your name at the top of the file as a comment, and submit it using /common/cs/submit/cs30-submit. Be sure to run this command from the directory containing your file.

If you have questions about anything, don't hesitate to ask!