Java Inner class demo program

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Table of Contents

An inner class is a class inside another class. The main purpose of using an inner class is to group related classes together.

Java program

import java.text.DecimalFormat;

public class Item
{
 private String description; // description
 private int itemNumber; // number
 private Cost cost; // Cost

 /**
 * Item constructor
 **/
 public Item(String desc, int itemNum, double wholesale, double retail)
 {
 description = desc;
 itemNumber = itemNum;
 cost = new Cost(wholesale, retail);
 }

 /**
 * RetailItem class toString method
 */
 public String toString() {
 String str;
 DecimalFormat dollar = new DecimalFormat("#,##0.00");
 str = "Description: " + description
 + "\nItem Number: " + itemNumber
 + "\nWholesale Cost: $"
 + dollar.format(cost.getWholesale())
 + "\nRetail Price: $"
 + dollar.format(cost.getRetail());
 return str;
 }

 /**
 * Inner Class
 */
 private class Cost
 {
 public double wholesalePrice;
 public double retailsalePrice;

 public double getWholesale() {
 return wholesalePrice;
 }

 public void setWholesale(double wholesale) {
 this.wholesalePrice = wholesale;
 }

 public double getRetail() {
 return retailsalePrice;
 }

 public void setRetail(double retail) {
 this.retailsalePrice = retail;
 }

 /**
 * Cost constructor
 */
 public Cost(double w, double r)
 {
 wholesalePrice = w;
 retailsalePrice = r;
 }
 }
}

Test Driver

/**
 * Item class
 */
public class InnerClassDemo
{
 public static void main(String[] args)
 {
 Item item = new Item("Rice Packet", 1001,1.75, 2.50);
 System.out.println(item);
 }
}

Screenshot

Inner class