#Chapter 6 Array Labs

6.1 Tracking Sales

Open Sales.java. Sales.java contains a Java program that prompts for and reads in the sales for each of 5 salespeople in a company. Sales are entered as integer values. It then prints out the id and amount of sales for each salesperson and the total number of sales. Study the code, then compile and run the program to see how it works.

As you complete this lab you should be able to run the main method as well as SalesTest.java to test your program.

Now modify the program as follows:

1. a) Complete the average method to compute and return the average of arr. Be sure to use the length instance variable and you may assume that the array is full. If the array does not have at least 1 element in it, throw an IllegalStateException

   b) In the main method, use your average method to print the average sales

2. a) Complete the indexOfMax method to compute and print the index of the maximum sales in arr.

   b) In the main method, use your indexOfMax method to print the index of the best sales person and the sales amount for that sales person.

3. a) Do the same thing for for an indexOfMin method.

   b) In the main method, use your indexOfMin method to print the index of the best sales person and the sales amount for that sales person.

4. Instead of always reading in 5 sales amounts, at the beginning ask the user for the number of sales people and then create an array that is just the right size. The program can then proceed as before.

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6.2 Shopping Cart

In this exercise you will complete a class that implements a shopping cart as an array of items. Opne the files Item.java and ShoppingCart.java and study the code to get an idea of how it works. The file Item.java contains the definition of a class named Item that models an item one would purchase at a store. An item has a name, price, and quantity (the quantity purchased). The file ShoppingCart.java implements the shopping cart as an array of Item objects.

Complete the ShoppingCart class by doing the following:

1. a) Declare an instance variable cart to be an array of Items and instantiate cart in the constructor to be an array holding capacity Items. (Note: capacity is an instance variable initialized to 5)

   b) Fill in the code for the addToCart method. This method should add the item to the cart and update the totalPrice instance variable (note this variable takes into account the quantity).

   c) Compile your class. (Note: No tester or driver class has been written yet. You are checking for syntax errors in your ShoppingCart class.)

2. a) Write a program ShopTest that simulates shopping. The program should have a loop that continues as long as the user wants to shop. Each time through the loop read in the name, price, and quantity of the item the user wants to add to the cart. After adding an item to the cart, the cart contents should be printed. Be sure not to add more than 5 items to your cart.

   b) Add a method getTotalPrice to the ShoppingCart class which returns the totalPrice of the cart. After the loop print a "Please pay ..." message with the total price of the items in the cart.

3. Use the following test data to test your program. Note the following example has 4 items (quantity of each items is a different value): The total should be 20.10

Item	Quantity	Price
milk	2	3.56
donuts	12	0.47
bread	1	4.24
oranges	5	0.62

Sample Output

  Would you like to go shopping? (yes or no)
  yes
  What would you like to buy?
  milk
  How much does it cost?
  3.56
  How many do you want?
  2
  Would you like to get anything else? (yes or no)
  yes
  What would you like to buy?
  donuts
  How much does it cost?
  0.47
  How many do you want?
  12
  Would you like to get anything else? (yes or no)
  yes
  What would you like to buy?
  bread
  How much does it cost?
  4.24
  How many do you want?
  1
  Would you like to get anything else? (yes or no)
  yes
  What would you like to buy?
  oranges
  How much does it cost?
  0.62
  How many do you want?
  5
  Would you like to get anything else? (yes or no)
  no
  
  Shopping Cart
  Item                Price  Quantity    Total
  milk                 3.56         2      7.12
  donuts               0.47        12      5.64
  bread                4.24         1      4.24
  oranges              0.62         5      3.10
  
  Total Price: $20.10

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6.3 Flexible Shopping Cart

In the previous exercise, your ShoppingCart was limited to 5 (capacity) items. Copy ShoppingCart.java into ShoppingCart2.java. In this exercise you will add a method to the ShoppingCart2 class to increase the capacity.

Complete the ShoppingCart2 class by doing the following:

1. Add a method increaseSize. This method will increase the size of cart by 3.
   • Create a temporary cart that is 3 items bigger than cart.
   • Write a for loop to loop through the cart array, adding the items to the temporary cart.
   • Write a statement to change the address of cart to the address of the temporary cart. Now cart is 3 items bigger.

    /**
    * Increases the size of the shopping cart by 3.
    */
    private void increaseSize()
    {
        
    }

2. Add logic to the addToCart method so that if the user adds an item to a full cart, the increaseSize method is called. The item is then added.

3. Test your changes. Try adding more than 5 items to your cart. Use the following test data:

Item	Quantity	Price
milk	2	3.56
donuts	12	0.47
bread	1	4.24
oranges	5	0.62
butter	1	3.24
yogurt	6	0.82
pepsi	1	2.45

Please pay $30.71

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6.4 Shopping Cart Using the ArrayList Class

In this exercise you will modify ShoppingCart to use the ArrayList class. Create a new project and copy the file Item.java from the previous lab. The class named Item models an item one would purchase. An item has a name, price, and quantity (thequantitypurchased). Copy ShoppingCart.java into ShoppingCart3.java. Copy ShopTest.java into ShopTest3.java and modify to use the ShoppingCart3 class.

ShopTest3.java will behave exactly like ShopTest2.java. The difference is the ShoppingCart3 class will store Item objects in an ArrayList, rather than an Array. Modify all of the methods to use the ArrayList syntax for adding and displaying items from the Cart ArrayList. Do not forget to import the ArrayList class at the top of your ShoppingCart3 class.

Test your code with the following items:

Item	Quantity	Price
milk	2	3.56
donuts	12	0.47
bread	1	4.24
oranges	5	0.62
butter	1	3.24
yogurt	6	0.82
pepsi	1	2.45

Please pay $30.71

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6.5 Card Game

Inspect the code in Card.java DeckOfCards.java and DeckOfCardsTest.java. Cards.java contains a Java program that contains two String variables – face and suit – to represent a specific Card. DeckOfCards contains an array of Card objects (52 cards in the deck). This class has two methods shuffle() which randomly mixes the deck of cards and dealCard() which returns the next Card to be dealt. The driver program DeckOfCardsTest shuffles the deck of cards and prints out each Card as it is dealt. Study the code, then compile and run the program to see how it works.

Choose one of the two following card games to implement (poker, blackjack). Deck of Cards and one of the games will count as one lab.

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Option 1 Five-Card-Poker

Card Game #1: Five-Card Poker Write a program using the classes you have already created that deals two five-card poker hands, evaluates each hand and determines which is better. Add the remaining methods to the DeckOfCard class or play poker with the hands already defined in the Deck of Cards lab.

Modify the program as follows:

1. Modify the program DeckOfCardsTest to deal a five card poker hand into a Card array named hand. Then modify class DeckOfCards to include methods that determine whether a hand contains (pass the hand array to the method) one of the following combinations of Cards:

   a. a pair

   b. two pairs

   c. three of a kind (e.g., three jacks)

   d. four of a kind (e.g., four aces)

   e. a straight (i.e., five cards of consecutive face values – can have different suits)

   f. a full house (i.e., two cards of one face value and three cards of another face value)

Hint 1: Add methods getFace and getSuit to class Card

Hint 2: Create a method in class DeckOfCards to total the hand (totalHand). Pass the hand array to the method and tally the number of each face in an integer array numbers. For example, if the hand contains 2 Queens, and 3 4’s, the numbers array will contain:

numbers

0	1	2	3	4	5	6	7	8	9	10	11	12
0	0	0	0	3	0	0	0	0	0	0	2	0

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Option 2 Black-Jack

Write a program using the classes you have already created to play Blackjack. The basic premise of the game is that you want to have a hand value that is closer to 21 than that of the dealer, without going over 21.

In blackjack, the cards are valued as follows:

• An Ace can count as either 1 or 11.
• The cards from 2 through 9 are valued at their face value.
• The 10, Jack, Queen, and King are all valued at 10.
• The suits of the cards do not have any meaning in the game. The value of a hand is simply the sum of the point counts of each card in the hand. For example, a hand containing (5,7,9) has the value of 21.
• The Ace can be counted as either 1 or 11. It's assumed to always have the value that makes the best hand.
• You may want to modify the Card class to contain an int variable value to hold the card’s point value.
• Add a method getValue() to return the Card’s point value.

Here is how the game is played:

1. The dealer deals himself and the player two cards.
2. Print only one of the dealer’s cards. The other is face down. If the dealer has blackjack (21) the dealer wins.
3. Print the players two cards and the total value. If the player has blackjack (21), he wins.
4. Ask the player if he wants to “hit” or “stay”. If he chooses “hit”, deal another card and display the total value. Keep prompting the user until they select “stay” or their total goes over 21, which is a “bust”.
5. The dealer must continue to deal himself cards UNTIL the total is 17 or over. Once the total is 17 or over, he stops dealing cards. Display the total value of the hand or “bust” if the hand is over 21.
6. Compare the values of the dealer and player’s hand and display the winner.