1.	Create the above system using a menu and implement it using switch statement. For example, in the above system implement the menu driven like..
i.	For setting a value of MRP and QUANTITY for the product.
ii.	For buying a product.
iii.	For searching a product.
iv.	To delete a product from storage.
v.	To show stored object data

Input:

import java.util.Scanner;
import java.util.HashMap;

public class MenuSystemPrac1{
	private static HashMap<String,HashMap<String,String>> productList = new  HashMap<String,HashMap<String,String>>();
	public static Scanner input = new Scanner(System.in);
	public static void main(String[] args) {
		
		menuList();
		int choice = 6;
		while(choice!=0){
			menu_selection(choice);
			System.out.print("Enter the choice :");
			choice = input.nextInt();
			input.nextLine();
		}
	}
	public static void menuList(){
		System.out.println("--------------------------------------------------------------");
		System.out.println("menu");
		System.out.println("--------------------------------------------------------------");
		System.out.println("1. For setting a value of MRP and QUANTITY for the product.");
		System.out.println("2. For buying a product.");
		System.out.println("3. For searching a product.");
		System.out.println("4. To delete a product from storage.");
		System.out.println("5. To show stored object data.");
		System.out.println("6. To Add data.");
		System.out.println("0. Exit.");
		System.out.println("--------------------------------------------------------------");
	}
	public static void menu_selection(int choice){
		switch(choice){
			case 1:updateProduct();
			break;
			case 2:buy();
			break;
			case 3:search();
			break;
			case 4:deleteProduct();
			break;
			case 5:showProductList();
			break;
			case 6:addProduct();
			break;
		}
	}
	public static void buy(){
		System.out.println("Enter the Name of Product You want to buy");
		String name = input.nextLine();
		if(productList.get(name)!=null){
			System.out.println("You bought below product");
			showProduct(productList.get(name).get("name"),productList.get(name).get("mrp"),productList.get(name).get("quntity"));
			System.out.println("---------------------------------------------");
			System.out.println("You will pay :" + productList.get(name).get("mrp"));
			System.out.println("---------------------------------------------");
		}else{
			System.out.println("Product is not available.");
		}
	}
	public static void save(String name,double mrp,int qun){
		HashMap<String,String> productData = new HashMap<String,String>();
		productData.put("name",name);
		productData.put("mrp",String.valueOf(mrp));
		productData.put("quntity",String.valueOf(qun));
		productList.put(name,productData);
	}
	public static void addProduct(){
		System.out.println("Enter the Name of Product :");
		String name = input.nextLine();
		System.out.println("Enter the MRP :");
		double mrp  = input.nextDouble();
		System.out.println("Enter the Quantity :");
		int qun = input.nextInt();
		input.nextLine();
		if(productList.get(name)==null){
			save(name,mrp,qun);
			System.out.println("Product added to List succesfully...\n");
		}else{
			System.out.println("Product is already available.\n");
		}
	}

	public static void  updateProduct(){
		System.out.println("Enter the Name of Product :");
		String name = input.nextLine();
		if(productList.get(name)!=null){
			System.out.println("Enter the MRP :");
			double mrp  = input.nextDouble();
			System.out.println("Enter the Quantity :");
			int qun = input.nextInt();
			save(name,mrp,qun);
			System.out.println("Product is Updated succesfully.\n");
		}else{
			System.out.println("Product is not available.\n");
		}
	}
	public static void deleteProduct(){
		System.out.println("Enter the Name of Product :");
		String name = input.nextLine();
		if(productList.get(name)!=null){
			productList.remove(name);
			System.out.println("Product is deleted successfully... \n");
		}else{
			System.out.println("Product is not available.\n");
		}
	}

	public static void search(){
		System.out.println("Enter Product name you want to search :");
		String name = input.nextLine();
		if(productList.get(name)!=null){
			showProduct(productList.get(name).get("name"),productList.get(name).get("mrp"),productList.get(name).get("quntity"));
		}
	}
	public static void showProductList(){
		for(String name : productList.keySet()){
			showProduct(productList.get(name).get("name"),productList.get(name).get("mrp"),productList.get(name).get("quntity"));
		}
	}
	public static void showProduct(String name,String mrp,String qun){
		System.out.println("-------------------------------");
		System.out.println("Name of Product : "+name);
		System.out.println("MRP of Product : "+mrp);
		System.out.println("Quntity of Product : "+qun);
		System.out.println("-------------------------------\n");
	}
	}