Solution to Test 1 CompSci 6 Spring 2007

Problem 1 - Part A

A. String

B. int pos, int pos2

C. Brodhead, Richard

D. C D E, A

E. It builds a new string that is everything after the second blank, 
followed by a comma, followed by the original first word. 

Problem 1 - Part B

A. 1, numbers

B. Integer

C. 18

D. It is the sum of the even numbers in the array

E. 
    int count = 0;
    for (int k=0; k < numbers.size(); k++)
    {
        if (numbers.get(k) % 2 == 0)
        {
            count += numbers.get(k);
        }
    }
    return count;

F. 
    int count = 0;
    int k = 0;
    while (k < numbers.size())
    {
        if (numbers.get(k) % 2 == 0)
        {
            count += numbers.get(k);
        }
        k++;
    }
    return count;

Problem 2 

A. Book

B. myAuthor = name;

   myAuthor is private in the Book class and not accessible by the PictureBook
    class. To fix it, the Book class should have a method to change the name
    of the author that is public, and then you could call that method. 
C.  

1. Correct, output is: Patterson

2. The constructor with two arguments is not defined. 

3. Correct, output is: Brown Hurd

4. Cannot convert a Book to a PictureBook.

Problem 3 Part A

Part A1

   public GroceryStore (Scanner input)
   {
      myItems = new ArrayList<String>();
      myPrices = new ArrayList<Double>();
      myQuantity = new ArrayList<Integer>();

      while (input.hasNext())
      {
         myItems.add(input.next());
         myPrices.add(input.nextDouble());
         myQuantity.add(input.nextInt());
      }
   }

Part A2

   // returns number of different types of items
   public int getNumberOfItems()
   {
      return myItems.size();
   }

Part A3

   // returns total number of items in store
   public int getTotalNumberOfItems()
   {
      int sum = 0;
      for (int k=0; k<myItems.size(); k++)
      {
         sum += myQuantity.get(k);
      }

      return sum;
   }

Part A4

   // returns price of specific item, returns -1 if item not in store
   public double getPriceOfitem(String item)
   {
      for (int k = 0; k< myItems.size(); k++)
      {
         if (myItems.get(k).equals(item))
            return myPrices.get(k);
      }

      return -1.0;
   }

Part A5

   public int getNumberOfItemsWithPrice(double minPrice, double maxPrice)
   {
      int count = 0;
      for (int k = 0; k< myItems.size(); k++)
      {
         if (myPrices.get(k) >= minPrice && myPrices.get(k) <= maxPrice)
         {
            count += 1;
         }
      }
      return count;
   }

Part A6

   public void addItem(String item, double price, int quantity)
   {
      for (int k=0; k<myItems.size(); k++)
      {
         if (myItems.get(k).equals(item)) // found
         {
            myPrices.set(k, price); 
            myQuantity.set(k, myQuantity.get(k) + quantity);
            return;
         }
      }
      
      myItems.add(item);
      myPrices.add(price);
      myQuantity.add(quantity);
   }

Part A6 (alternate)

   public void addItem(String item, double price, int quantity)
   {
      boolean nochange = true;
      for (int k=0; k<myItems.size(); k++)
      {
         if (myItems.get(k).equals(item)) // found
         {
            myPrices.set(k, price); 
            myQuantity.set(k, myQuantity.get(k) + quantity);
            nochange = false;
         }
         
      }
      
      if (nochange)
      {
        myItems.add(item);
        myPrices.add(price);
        myQuantity.add(quantity);
      }
   }

Part A7

   public ArrayList<String> ItemsInCart (String cart)
   {
      ArrayList<String> allitems = new ArrayList<String>();
      while (cart.length()> 0)
      {
         int pos = cart.indexOf(" ");
         if (pos == -1) // only 1 word left
         {
            allitems.add(cart);
            cart = "";
         }
         else 
         {
            allitems.add(cart.substring(0,pos));
            cart = cart.substring(pos+1);
         }
      }
      return allitems;
   }


Part A7 (alternate)

   public ArrayList<String> ItemsInCart (String cart)
   {  ArrayList<String> allitems = new ArrayList<String>();
      Scanner in = new Scanner(cart)
      while (in.hasNext())
      {
          allitems.add(in.next());
      }
      return allitems;
   }

Part A8

   public double RingUpBasket(String cart)
   {
      ArrayList<String> allitems = ItemsInCart(cart);
      double price = 0.0;
      double sum = 0.0;
      for (String item: allitems)
      {
         price = getPriceOfitem(item);
         System.out.println("item " + item + " price is " + price);
         if (price >0)
         {
            sum += price;
         }
         else 
         {
            System.out.println("ERROR: item " + item + " not in db");
         }
      }   
      return sum;   
   }

Part B
   private ArrayList<GroceryItem> myItems;

Part B1
   public GroceryStore2 (Scanner input)
   {
      myItems = new ArrayList<GroceryItem>();
      while (input.hasNext())
      {
         myItems.add(new GroceryItem(input.next(), input.nextDouble(), 
               input.nextInt()));
      }
   }

Part B1  (alternate body of while loop - write it all out)
      while (input.hasNext())
      {
         String item = input.next();
         Double price = input.nextDouble();
         int quantity = input.nextInt();
         GroceryItem temp = new GroceryItem(item, price, quantity);
         myItems.add(temp);
      }

Part B2
   public double getPriceOfitem(String item)
   {
      for (GroceryItem stockItem: myItems)
      {
         if (stockItem.getItem().equals(item))
            return stockItem.getPrice();
      }
      return -1.0;
   }