Practical 4

Write a Java program using Map interface containing list of items having keys and associated values and perform the following operations:

1. Add items in the map.

2. Remove items from the map

3. Search specific key from the map

4. Get value of the specified key

5. Insert map elements of one map in to other map.

6. Print all keys and values of the map.

Book.java

package com.hiraymca;

/**

*

* @author VIKRAM

*/

public class Book {private int id; private String name; private String author;

public Book()

{

}

public Book(int id, String name, String author) {this.id = id;

this.name = name;

this.author = author;

}

public int getId() {

return id;

}

public void setId(int id) {this.id = id;

}

public String getName() {return name;

}

public void setName(String name) {this.name = name;

}

public String getAuthor() {return author;

}

public void setAuthor(String author) {this.author = author;

}

}

mapExample.java

package com.hiraymca;

import java.util.HashMap; import java.util.Map;

import java.util.Scanner;

/**

*

* @author VIKRAM

*/

public class mapExample {

public static void main(String []args)

{

//Creating map of books

Map<Integer,Book>map=new HashMap<Integer,Book>();

//Creating books

Book b1=new Book(101,”Let us C”,”Yashwant Kanetkar”);

Book b2=new Book(102,”Data communication & Networking”,”Forouzan”); Book b3=new Book(103,”Operating System”,”Achuyut Godbole”);

Book b=new Book();

//Adding books to map map.put(1,b1);

map.put(2,b2);

map.put(3,b3);

//Traversing the map

for(Map.Entry<Integer, Book> entry:map.entrySet()){int key=entry.getKey();

b=entry.getValue();

System.out.println(b.getId()+” “+b.getName()+” “+b.getAuthor());

}

//Removing element from map map.remove(2);

//Traversing the map after removing System.out.println();

System.out.println(“Traversing map after removing 2nd element”); for(Map.Entry<Integer, Book> entry:map.entrySet()){

int key=entry.getKey(); b=entry.getValue();

System.out.println(b.getId()+” “+b.getName()+” “+b.getAuthor());

}

//searching for specific entry int mykey;

Scanner sc=new Scanner(System.in); System.out.print(“Enter the key “); mykey=sc.nextInt();

for(Map.Entry<Integer, Book> entry:map.entrySet())

{int key=entry.getKey();

b=entry.getValue();

System.out.println(b.getId()+” “+b.getName()+” “+b.getAuthor());

}

}

}

Output

run:

101 Let us C Yashwant Kanetkar

102 Data communication & Networking Forouzan 103 Operating System Achuyut Godbole

Traversing map after removing 2nd element

101 Let us C Yashwant Kanetkar

103 Operating System Achuyut Godbole Enter the key 101

101 Let us C Yashwant Kanetkar