Practice Assignment

Information

1. Write a program that similates rolling 5 dice like in the game of Yahtzee. Yahtzee is kind of like the card game poker, but using dice instead of cards. On Linux, the game is called Kiriki.

   You will ask the user how many times to roll the 5 dice. For each roll, you will need to generate 5 random numbers from 1 to 6. You are to count how many times all of the dice are the same value (5 of a kind, a Yahtzee). After all of the rolls have been done, you will display how many times all of the dice were the same and the percentage.

   The actual probability of rolling a "5 of a kind" is 1/1296, or about 0.0007716. (The Internet is rife with all kinds of Yahtzee-related stuff.)

   Here is the output from the program run interactively:

   How many times do you want to roll the dice? (0=quit) 100
   After 100 rolls, you had 5 of a kind 0 times.
   This is a percentage of 0.00000000.
   
   How many times do you want to roll the dice? (0=quit) 1000
   After 1000 rolls, you had 5 of a kind 2 times.
   This is a percentage of 0.00200000.
   
   How many times do you want to roll the dice? (0=quit) 1000
   After 1000 rolls, you had 5 of a kind 0 times.
   This is a percentage of 0.00000000.
   
   How many times do you want to roll the dice? (0=quit) 1000
   After 1000 rolls, you had 5 of a kind 1 time.
   This is a percentage of 0.00100000.
   
   How many times do you want to roll the dice? (0=quit) 10000
   After 10000 rolls, you had 5 of a kind 8 times.
   This is a percentage of 0.00080000.
   
   How many times do you want to roll the dice? (0=quit) 20000
   After 20000 rolls, you had 5 of a kind 10 times.
   This is a percentage of 0.00050000.
   
   How many times do you want to roll the dice? (0=quit) 12345
   After 12345 rolls, you had 5 of a kind 11 times.
   This is a percentage of 0.00089105.
   
   How many times do you want to roll the dice? (0=quit) 0
   

   The program continues to run until the user types in 0 (zero) for the number of rolls.

   Questions: What do you notice as you increase the number of rolls? How large of an integer can you provide? Caution: A very large integer could cause the program to take a long time to finish. (Press Ctrl-C to stop the program, if you get tired of waiting.)

   The name of the file should be dice1.c and the command to compile it will look like this:

   gcc -Werror -Wall -Wextra -ansi -pedantic -O2 -Wno-unused-result -o dice1 dice1.c PRNG.c
   

   Files:
   • Here is a sample input file and output file for you do diff with. Remember, using redirection will not show the actual numbers or provide a newline.
   • Here's a starting point for your code: dice1.c (You'll need to rename it.)

   • Random number generator files (put these in the same directory as your C file)
     • - Header file (PRNG.h): HTML Text
     • - Implementation (PRNG.c): HTML Text

Notes

• Approximate number of lines of code: 25

• You should use a do...while loop (as usual) to get the user's input.
• You don't have to worry about invalid input. You can assume that the user is going to input an integer greater than or equal to 0.
• You will have multiple scopes in your program (likely in main). This means you do not have to define all of your variables at the top of the function (it's OK if you do). But, if you want to practice defining variables in other scopes, this is a good time to do so. The rule-of-thumb is: Define your variables in the scope where they are used.

• Don't use the built-in pseudo-random number generator. Use the one provided in the files above. Refer the CS120 notes on random numbers, if you need to. You don't have to create any functions yourself, just use the RandomInt function from the PRNG files. To generate a random number between 1 and 6 and assign to an integer named value:

value = RandomInt(1, 6);

Also, the PRNG is already seeded for you in the partial dice1.c file above. Don't change it.
• To run the code non-interactively (redirecting input and output), you would do this:

  dice1 < input.txt > myoutput.txt
  

  and then diff with the provided output.

Mead trivia: Yahtzee was one of the first computer "games" I ever wrote. I coded in SanyoBasic on the Sanyo MBC550 (but mine had only one floppy disk drive). I had to write my own games because there was no software for this computer! I also had to upgrade the RAM from 128K to 256K (yes, that's a K) to do the 2 color 640x200 graphics on a low end video chip because I wanted to draw the dice (with pathetic animation) on the screen. I wish I still had that code so I could show students how NOT to write code. (Butt-ugly comes to mind.)