Question

Writing in Java ,using Arraylist and collection please.

3. Write a simple phonebook program that reads in a series of name-number pairs from the user (that is, name and number on one line separated by whitespace) and stores them in a Map from Strings to Integers. Then ask the user for a name and return the matching number, or tell the user that the name wasn't found.

Answer 1

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

public class PhoneBook {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        Map<String, String> map = new HashMap<>();
        String name, number, choice;
        do {
            System.out.print("Enter name: ");
            name = in.next();
            System.out.print("Enter number: ");
            number = in.next();
            map.put(name, number);
            System.out.print("Do you want to try again(y or n): ");
            choice = in.next();
        } while (!choice.equalsIgnoreCase("n"));
        System.out.print("Enter name to search for: ");
        name = in.next();
        if (map.containsKey(name)) {
            System.out.println(map.get(name));
        } else {
            System.out.println(name + " is not in the phone book");
        }
    }
}

Enter name: ronaldo Enter number: 7 Do you want to try again(y or n): Y Enter name: messi Enter number: 10 Do you want to try again(y or n): Y Enter name: bale Enter number: 11 Do you want to try again(y or n): n Enter name to search for: ronaldo