Question

Instructions

1. Create a class named after your favorite object in the whole world. For example, if you love pizza, then create a class called Pizza.java. This class should not have a main method (1 point)

2. Create Instance Variables (attributes) (2 point)

• Create at least 3 private instance fields (attributes) for your class
• You must use at least 3 different data types for your fields

3. Create getter (accessor) and setter (mutator) methods  

• Create a getter (accessor) method for each of your instance variables (1 point)
• Create a setter (mutator) method for each of your instance variables  (1 point)

4. Create a Method to display your data (1 point)

• Create a method called display, that simply prints out the values of all instance variables of your object

5. Create any other method of your choice that increments or decrements any one of the objects instance fields. Test out the method for at least one of your objects. (2 point)

6. Create 2 Constructors

• Create a default constructor (no parameters) that assigns all your instance variables to default values  (1 points)
• Create a parameterized constructor that takes all instance variables as parameters, and sets the instance variables to the values provided by the parameters (1 points)

7. Testing your program (2 points)

• Create a class called Driver.java. This class will contain your main method
• Create 2 instances of your class by using the default constructor.
  • Call all your objects set methods to assign values to your object
• Create 2 instances of your class by using the parameterized constructor

8. Put all of your objects in an array, loop through the array, and call the display method on each object (2 points)

9. Add JavaDoc style comments above all methods and classes   (1 point)

Answer 1

/**
* @author pyari
* Defines class Pizza
*
*/
class Pizza
{
   // Instance variables to store pizza information
   private String topping;
   private String size;
   private double price;
   private int quantity;
  
   /**
   * Default constructor to assign "Unknown" to string instance variables
   * 0 to double and integer instance variables
   */
   public Pizza()
   {
       topping = "Unknown";
       size = "Unknown";
       price = 0.0;
       quantity = 0;      
   }
  
   /**
   * Parameterized constructor to assign parameter values to instance variables
   * @param topping - type of topping for pizza
   * @param size - size of the pizza
   * @param quantity - number of pizza ordered
   * @param price - price of each pizza
   */
   public Pizza(String topping, String size, int quantity, double price)
   {
       this.topping = topping;
       this.size = size;
       this.price = price;
       this.quantity = quantity;
   }
  
   /**
   * Method to increase the price of the pizza by given parameter percentage
   * @param percent - price percentage to increase
   */
   public void increasePriceByPercent(double percent)
   {
       price += (price * percent) / 100.0;
   }
  
   // Getter methods
   public String getTopping()
   {
       return topping;
   }
   public String getSize()
   {
       return size;
   }
   public double getPrice()
   {
       return price;
   }
   public int getQuantity()
   {
       return quantity;
   }
  
   // Setter methods
   public void setTopping(String topping)
   {
       this.topping = topping;
   }
   public void setSize(String size)
   {
       this.size = size;
   }
   public void setPrice(double price)
   {
       this.price = price;
   }
   public void setQuantity(int quantity)
   {
       this.quantity = quantity;
   }
  
   /**
   * Method to display pizza information
   */
   public void showPizza()
   {
       System.out.println("\n Topping: " + topping + "\n Size: " + size +
               "\n Quantity: " + quantity + "\n Price: $" + price +
               "\n Amount to pay: $" + (quantity * price));
   }
}// End of class Pizza

/**
* @author pyari
* Driver class to test the pizza class methods
*
*/
public class PizzaDriver
{
   // main method definition
   public static void main(String []s)
   {
       // Declares an array of object of class Pizza of size 4
       Pizza [] pizza = new Pizza[4];
      
       // Creates a pizza object using default constructor
       pizza[0] = new Pizza();
       // Calls the setter method to set data
       pizza[0].setTopping("Mushrooms");
       pizza[0].setSize("Small");
       pizza[0].setQuantity(10);
       pizza[0].setPrice(50.63);
      
       // Creates a pizza object using default constructor
       pizza[1] = new Pizza();
       // Calls the setter method to set data
       pizza[1].setTopping("Cheese");
       pizza[1].setSize("Large");
       pizza[1].setQuantity(4);
       pizza[1].setPrice(90.12);
      
       // Creates pizza object using parameterized constructor
       pizza[2] = new Pizza("Onions", "Medium", 8, 61.12);
       pizza[3] = new Pizza("Pepperoni", "extraLarge", 6, 78.33);
      
       // Loops till number of pizza ordered      
       for(int c = 0; c < pizza.length; c++)
           // Calls the method to display each pizza information
           pizza[c].showPizza();
      
       // Calls the method to increase the pizza price by 10%
       pizza[1].increasePriceByPercent(10.0);
       System.out.println("\n After increasing the price of pizza One by 10%");
       // Calls the method to display pizza information
       pizza[1].showPizza();
   }// End of main method
}// End of driver class

Sample Output:

Topping: Mushrooms
Size: Small
Quantity: 10
Price: $50.63
Amount to pay: $506.3

Topping: Cheese
Size: Large
Quantity: 4
Price: $90.12
Amount to pay: $360.48

Topping: Onions
Size: Medium
Quantity: 8
Price: $61.12
Amount to pay: $488.96

Topping: Pepperoni
Size: extraLarge
Quantity: 6
Price: $78.33
Amount to pay: $469.98

After increasing the price of pizza One by 10%

Topping: Cheese
Size: Large
Quantity: 4
Price: $99.132
Amount to pay: $396.528