Constructors in Java

Chapter 11

Constructors in Java

Class 10 - Logix Kips ICSE Computer Applications with BlueJ

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Java Program: Create a Pizza Class with Constructor and Cost Calculation

Create a class named Pizza that stores details about a pizza. It should contain the following:

Instance Variables:
String pizzaSize — to store the size of the pizza (small, medium, or large)
int cheese — the number of cheese toppings
int pepperoni — the number of pepperoni toppings
int mushroom — the number of mushroom toppings

Member Methods:
Constructor — to initialise all the instance variables
CalculateCost() — A public method that returns a double value, that is, the cost of the pizza.
Pizza cost is calculated as follows:

Small: Rs.500 + Rs.25 per topping
Medium: Rs.650 + Rs.25 per topping
Large: Rs.800 + Rs.25 per topping

PizzaDescription() — A public method that returns a String containing the pizza size, quantity of each topping, and the pizza cost as calculated by CalculateCost().

Program Type 1: Java Program to Create a Pizza Class with Constructor and Cost Calculation

Java

public class Pizza
{
    String pizzaSize;
    int cheese;
    int pepperoni;
    int mushroom;
   
    public Pizza(String size,
                    int tc,
                    int tp,
                    int tm) {
        pizzaSize = size;
        cheese = tc;
        pepperoni = tp;
        mushroom = tm;
    }
   
    public double CalculateCost()   {
        double totalCost = 0;
        double topCost = 25 * (cheese + pepperoni + mushroom);
       
        if (pizzaSize == "small")
            totalCost = 500 + topCost;
        else if(pizzaSize == "medium")
            totalCost = 650 + topCost;
        else
            totalCost = 800 + topCost;
           
        return totalCost;
    }
   
    public String PizzaDescription()    {
        double cost = CalculateCost();
        String desc = "Size: " + pizzaSize
        + " Cheese: " + cheese
        + " Pepperoni: " + pepperoni
        + " Mushroom: " + mushroom
        + " Cost: Rs. " + cost;
       
        return desc;
    }
   
    public static void main(String args[])  {
        Pizza p = new Pizza("medium", 15, 5, 10);
        String desc = p.PizzaDescription();
        System.out.println(desc);
    }
   
   
}

Output

Sample Output 
Size: medium Cheese: 15 Pepperoni: 5 Mushroom: 10 Cost: Rs. 1400.0

Program Type 2: Pizza Class with Constructor & Cost Calculation

Java

import java.util.Scanner;
 
public class Pizza
{
    // Instance Variables
    String pizzaSize;
    int cheese;
    int pepperoni;
    int mushroom;
 
    // Constructor
    public Pizza(String size, int cheeseToppings, int pepperoniToppings, int mushroomToppings)
    {
        pizzaSize = size.toLowerCase();
        cheese = cheeseToppings;
        pepperoni = pepperoniToppings;
        mushroom = mushroomToppings;
    }
 
    // Method to calculate cost
    public double CalculateCost()
    {
        double basePrice = 0;
 
        if(pizzaSize.equals("small"))
            basePrice = 500;
        else if(pizzaSize.equals("medium"))
            basePrice = 650;
        else if(pizzaSize.equals("large"))
            basePrice = 800;
        else
        {
            System.out.println("Invalid Pizza Size!");
            return 0;
        }
 
        int totalToppings = cheese + pepperoni + mushroom;
 
        return basePrice + (25 * totalToppings);
    }
 
    // Method to return description
    public String PizzaDescription()
    {
        return "Pizza Size: " + pizzaSize +
               "\nCheese Toppings: " + cheese +
               "\nPepperoni Toppings: " + pepperoni +
               "\nMushroom Toppings: " + mushroom +
               "\nTotal Cost: Rs." + CalculateCost();
    }
 
    // Main Method (Single Program)
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
 
        System.out.println("Enter Pizza Size (Small / Medium / Large): ");
        String size = sc.next();
 
        System.out.println("Enter number of Cheese toppings: ");
        int cheese = sc.nextInt();
 
        System.out.println("Enter number of Pepperoni toppings: ");
        int pepperoni = sc.nextInt();
 
        System.out.println("Enter number of Mushroom toppings: ");
        int mushroom = sc.nextInt();
 
        // Create Pizza Object
        Pizza p = new Pizza(size, cheese, pepperoni, mushroom);
 
        // Display Details
        System.out.println("\n----- Pizza Details -----");
        System.out.println(p.PizzaDescription());
 
        sc.close();
    }
}

Output

Sample Output 
Enter Pizza Size (Small / Medium / Large):
Medium
Enter number of Cheese toppings:
2
Enter number of Pepperoni toppings:
1
Enter number of Mushroom toppings:
3

----- Pizza Details -----
Pizza Size: medium
Cheese Toppings: 2
Pepperoni Toppings: 1
Mushroom Toppings: 3
Total Cost: Rs.800.0