Homework 4: Word Play & Blackjack

Set Up

In this assignment you will solve some problems using both recursion and loops.

To work on this homework, follow these steps:

On Mac, open the Terminal program. On Windows, open the PowerShell program.
Log into goldengate by using the ssh command from your personal laptop: ssh your-username@goldengate.cs.brynmawr.edu.
Run these commands:

$ cd cs113
$ ls

If you see a homeworks directory, cd into it. Then, call mkdir hw4 to create your homework 4 directory. Finally, call cd hw4.

For each of the problems below, we will use the vim editor. You will need to create a java file for each problem. For example, for the first problem you will call vim WordLoops.java.

Remember your vim commands:

vim Filename.java: creates a file named Filename.java
i: enter insert mode
esc: exit insert mode (you must exit insert mode in order to save and quit)
:wq: save the file and close vim

1. Word Play

Write a program called WordLoops.java that implements the following methods. Make sure to test the methods in the file’s main method.

1.1 removeLetter

Write a method called removeLetter that takes a String and an array of letters and returns the String but will all instances of the letters removed. Implement this method using a for loop.

For example:

class WordLoops {
  public static void main(String[] args) {
    String s = removeLetter("asdfghsassaaaae", 'a');
    System.out.println(s);
    // will print: sdfghssse
  }

  public static String removeLetter(String s, char c) {
    // Your code here
  }

}

NOTE: You may NOT use the replace() function. Use of this function will give you zero credit on this problem.

1.2 removeLetters

Write a method called removeLetters that takes in a String and an array of letters and returns a String but will all instances of the letters removed. Implement this method using a while loop.

For example:

class WordLoops {
  public static void main(String[] args) {
    String s = removeLetters("asdfghsassaaaae", ['a', 's']);
    System.out.println(s);
    // will print: dfghe
  }

  public static String removeLetters(String s, char[] chars) {
    // Your code here

  }

}

NOTE: You should use your removeLetter function from section 1.1.

2. Blackjack

Write a program called BlackJack.java that will allow a user to play a simplified version of BlackJack. The rules of BlackJack are as follows:

Each card has a value ranging from 1 to 11 (inclusive).
The player starts with two cards.
The house starts with two cards. The player is shown just one of the house’s cards.
Until the value of the player’s hand (i.e. the sum of the value of their cards) is greater than or equal to 21, the player has two options: “Hit” or “Stand”.
If the player chooses “Hit”, they are given another card.
If the value of the player’s hand is ever greater than 21, the player automatically looses.
Once the player chooses “Stand”, their turn ends
If the value of the dealer’s hand is less than 15, then give them another card chosen at random.
If the value of the dealer’s hand is greater than or equal to the player’s hand, the dealer wins. Otherwise the player wins (assuming they did not go over 21).

Below are multiple examples showing how your program should work.

Example 1

$ java BlackJack
One of the dealer's cards is 5
Your hand's value is 12. What would you like to do:
HIT
Your hand's new value is 22.
You lost - goodbye!

Example 2

$ java BlackJack
One of the dealer's cards is 10
Your hand's value is 13. What would you like to do:
HIT
Your hand's new value is 20. What would you like to do:
STAY
The dealer's hand is 19.
You won - congrats!

Example 3

$ java BlackJack
One of the dealer's cards is 11
Your hand's value is 22.
You lost - goodbye!

Example 4

$ java BlackJack
One of the dealer's cards is 9
Your hand's value is 5. What would you like to do:
HIT
Your hand's new value is 7. What would you like to do:
HIT
Your hand's new value is 11. What would you like to do:
HIT
Your hand's new value is 18. What would you like to do:
STAY
The dealer's hand is 12.
The dealer's hand is 15.
The dealer's hand is 21.
You lost - goodbye!

Note 1: To generate a random number for a card value:

int randomNum = (int) (Math.random() * 11) + 1;

Note 2: Your random cards can have values from 1 to 11.

Note 3: You do not need to keep track of what cards have been used in the deck. You can just create random cards each time you need them.

Grading Rubric

This assignment will be out of 12 points:

Word Play: 4 points
Blackjack: 8 points

Submitting

In a text file (call vim readme.txt) answer the following questions:

How much time did you spend on the homework?
What did you learn from the homework?

For 2 extra credit points: Run this command on your java files before submitting: astyle --style=java Example.java. Replace Example with the name of your java file, for example: Numbers.

Finally, you need to copy your files from the server to your personal computer for submission.

Close your connection to goldengate (type exit), and then run the following command:

$ scp -r <username>@goldengate.cs.brynmawr.edu:/home/<username>/cs113/homeworks/hw4/ .

Make sure to replace <username> with your username. There is a space between hw4/ and .. scp is a command to secure-copy files from one server to another. In this case, from goldengate to your own machine.

Submit the following files to the assignment called HW04 on Gradescope.

WordPlay.java
Blackjack.java
readme.txt