HW #6: Yahtzee

Part 2 -- due 11:59pm Tuesday, March 6

Remember to run update21 to get the files needed for this assignment. The program handin21 will only submit files in the cs21/homework/6 directory.

Your programs are graded on both correctness and style. Please review the comments regarding programming style on the main page

Some of the problems will have optional components that allow you to further practice your skills in Python. Optional portions will not be graded, but may be interesting for those wanting some extra challenges.

If you would like some more practice with while loops, functions, and if statements, we have posted some smaller warmup problems that you can try. Working on these problems will help you practice the core concepts before working on the larger assignment. They are entirely optional.

In the second part of this two part assignment, you will extend your Yahtzee program to play a full game of Yahtzee. In addition to the code you wrote last week, you will make use of the ScoreCard class installed on the CS system. You can use import ScoreCard and help(ScoreCard) to learn more about this class and its methods. You will also need a small function called scoreList that we put in the update21 directory. Before working on this assignment, copy your yahtzee.py file from your homework/5/ to your homework/6/ directory. Modify only the copy in homework/6/. You may also want to import the ScoreCard class and play with the member functions before using the class in your code. Some sample code is shown below.

from ScoreCard import *
s = ScoreCard()
s.setScore(0, 100)
res = s.getScore(0)
if s.isFree(0):
    print "Category is free"
else:
    print "Category is taken"
  

If you want to work on the assignment on your home computer, you will need the graphics and ScoreCard library files. You can Download these files, but remember that only files that are in your homework/6/ folder in computer science will be graded. You do not need to upload the ScoreCard and graphics file when you upload your assignment.

Modify your program to implement the following.

Modify the reroll function to ensure valid input. If the user enters invalid dice positions, warn the user that some choices will be ignored, or prompt the user to enter only valid input. The program should not crash if the user enters invalid choices.

Implement the function chooseCat(s, dice) that takes as input two parameters: a ScoreCard s and a list of dice values dice. The chooseCat function should prompt the user to choose a category from those listed on the scorecard and then update the score card once an acceptable category has been chosen.

Your function must check that the user entered a valid category. A valid category must be a letter value between 'N' and 'Z' and must be a category that has not already been used. Certain member functions in the ScoreCard class can be used to check if a category has already been selected. In each of the member functions, the categories are indexed by a numerical value between 0 and 15 inclusive. The mapping of categories to numbers can be found using help(ScoreCard). If a user selects an invalid category, inform the user of the mistake and prompt the user again until they enter a valid answer.

Once you have implemented chooseCat modify your main() function to play a full game (13 turns) of Yahtzee. You will need to create an instance of the ScoreCard class. After every roll or re-roll, you should call the method displayPossibles in the ScoreCard class to update the scorecard with the appropriate values, at the end of the final re-roll, call your chooseCat function so the user can select a category in which to score his/her roll.

In addition to the standard scoring for each category defined in last week's assignment, Yahtzee has two bonus scoring category. The first bonus is called the Upper Bonus and is awarded to a player who scores a total of 63 or more points in the first six categories (Ones, Twos, Threes, Fours, Fives, and Sixes). This upper Bonus is worth 35 points. Implement a function that takes a ScoreCard as input and sets the Upper Bonus category (number 13 in the ScoreCard class) to 35 points if the user has 63 or more total points in the first six categories.

A Yahtzee Bonus is awarded to player who has already scored 50 points in the Yahtzee category and rolls another Yahtzee. On any second or subsequent Yahtzee, the player is awarded a 100 point Yahtzee bonus and the player must still select a category other than Yahtzee (which is already taken) to play his/her score. This Yahtzee Bonus can be awarded multiple times. For example, if a player rolls [2,2,2,2,2] an places this roll in the Yahtzee category, he or she receives 50 points for this Yahtzee. If later in the game the player rolls [3,3,3,3,3], he/she is awarded 100 points and must place this roll in another free category other than Yahtzee. If the player places the roll [3,3,3,3,3] in the Threes category, he/she receives an additional 15 points, or 115 total for that turn. Implement a function that takes a ScoreCard and a list of dice roll values as input and awards a Yahtzee bonus if the roll is a second or subsequent Yahtzee. To update the Yahtzee Bonus slot on the score card, use category number 14 in the ScoreCard class. Make sure you do not assign a Yahtzee Bonus to a player on the first Yahtzee.

After implementing both bonuses, modify chooseCat or main to check for both bonuses and update the ScoreCard accordingly. Also compute the total value for the entire ScoreCard. The total value is stored as category number 15 in the ScoreCard class.

Test your program to make sure it works. Play a few games of Yahtzee, or have your friends play. Make sure the program does not crash even if the user enters bad input values. If you want to quit the game or start over in the middle of playing a game, you can press Ctrl-C to exit. Note that you will need to use except IndexError:, except NameError:, etc. instead of just except: so that you do not catch the Ctrl-C keypress.

As noted above, these questions are NOT required to receive full credit. There are many extensions you could add to this program. Here are a few we thought might be interesting.

Two player mode

Modify your program to support two or more players. Each player should have their own score card. Adding two player support is a straightforward extension if designed properly. You main only need to modify the main function.

Early category selection

Currently, a user is asked to reroll the dice twice on each turn. A user can choose to reroll no dice on each reroll, but a better option might be to allow the user to pick a category after the first roll if the user decides not to reroll any dice. Implement this feature.

Cheat mode

Testing Yahtzee can be difficult as each roll is random. Implement a cheat mode where you can select the dice value on each roll. How high of a score can you get including bonuses in this cheat mode? You can either switch cheat mode on or off by changing the code and running the program again, or hiding the cheat mode as an "Easter egg" — an undocumented feature in the program. For example "cheat" is an unlikely input for which dice you want to reroll, but perhaps this secret code could toggle the cheat mode in the reroll function. Be creative.

Graphical dice

Add a graphical window that displays actual dice. You may want to refer to Chapter 10.6 in the text for an example of drawing dice (The example uses classes, but you should be able to glean enough information from the example to draw your own dice without using classes.) If you want to extend the graphical display further, allow the user to select the dice with mouse clicks instead of the keyboard.

High Score

Add an option to save your highest score. For this extension, you will need to know how to read and write files. See Chapter 4.6 in the text for an example of how to do this.

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Last updated: Tuesday, September 22, 2020 at 01:07:41 PM