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Learning Profile for Assignment #2, And Question #4

Name: Mo Khan Student ID: 3431709

  1. Problem Statement:

Craps is a dice game where two dice are rolled. Each die has six faces representing values:

1, 2, 3, 4, 5, or 6.

1. If the sum is 2, 3, or 12 (called craps), you lose;
1. If the sum is 7 or 11 (called natural), you win;
1. If the sum is any other value (4, 5, 6, 8, 9, or 10), a value point is established, and you continue to roll until you either roll a sum of the value point or a 7.
  If the sum of the new roll is equal to the value point, then you win; if the sum of the new roll is equal to 7, then you lose.
  Remember, in option (III), you continue to roll until you get a 7 or the value point.

Sample runs:

  • You rolled 5 + 6 = 11; you win
  • You rolled 1 + 2 = 3; you lose
  • You rolled 2 + 2 = 4; you establish the value point 4; – Roll again 2 + 3 = 5; roll – Roll again 2 + 1 = 3; roll – Roll again 2 + 2 = 4; you win
  • You rolled 2 + 6 = 8; you establish the value point 8; – Roll again 4 + 4 = 8; you win
  • You rolled 3 + 2 = 5; you establish the value point 5; – Roll again 1 + 1 = 2; roll – Roll again 2 + 2 = 4; roll
  • Roll again 1 + 1 = 2; roll
  • Roll again 3 + 4 = 7; you lose

Develop a program that plays craps with a player three times. At the end, the program prints the number of times the player won and the number of times the player lost.

  1. Description of the Code:

I solved this problem by creating a class called RandomSumGame as per the class diagram. I added two instance variables named wins and losses to keep track of how many times the player won or lost.

To try to make the API of this class more testable, I chose to pass the PrintStream in as a parameter to the constructor. This example of dependency injection, made it possible to write unit tests to ensure the proper output is printed to the stream.

To simplify the problem, I split it up into two types of game play. The rules for the initial roll is slightly different for the rules for subsequent rolls. I created two methods named firstPlay and subsequentPlay. This made it easy to focus on the rules for the initial roll in the firstPlay method and the rules for the subsequent roles in the subsequentPlay method.

To roll the dice, I extracted a method called roll that returns a random number between 1 - 6.

To keep track of the wins/losses, I delegating to the win or lose methods to print a message to the screen and increment a win/loss counter.

In the main method, I added a header for the game, then created an instace of the game, ran 3 rounds of the game and printed the final results afterwards.

There were some unneccessary instance variables, but I kept them to ensure that I satisfy the desired API described in the class diagram. In a few cases, local variables and recursion was more than enough.

I used recursion to handle subsequent rolls when a value point is established. With any recursion it’s important to have a solid base case. In this case the base case was either rolling a 7 or the value point. These values are randomly generated, so it is possible to produce an infinte loop due to randomness.

  1. Errors and Warnings:

  2. Sample Input and Output:

  3. 3 losses

```bash
Welcome to Craps
================

Game 1
You rolled: 5
Value point established: 5
You rolled: 7
You lose.

Game 2
You rolled: 6
Value point established: 6
You rolled: 5
You rolled: 9
You rolled: 7
You lose.

Game 3
You rolled: 3
Craps! You lose.

================
Wins: 0
Losses: 3
```
  1. 3 wins
```bash
java -cp target/assignment2*.jar ca.mokhan.comp268.App 4
Welcome to Craps
================

Game 1
You rolled: 7
Natural! You win!

Game 2
You rolled: 7
Natural! You win!

Game 3
You rolled: 5
Value point established: 5
You rolled: 6
You rolled: 4
You rolled: 8
You rolled: 5
You win!

================
Wins: 3
Losses: 0
```
  1. 2 wins, 1 loss
```bash
Welcome to Craps
================

Game 1
You rolled: 4
Value point established: 4
You rolled: 3
You rolled: 9
You rolled: 7
You lose.

Game 2
You rolled: 8
Value point established: 8
You rolled: 8
You win!

Game 3
You rolled: 8
Value point established: 8
You rolled: 2
You rolled: 8
You win!

================
Wins: 2
Losses: 1
```
  1. Discussion: