HashMapPractice.java

package exercises.Lesson2;

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

public class HashMapPractice {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        HashMap<Integer, String> studentRoster = new HashMap<>();
        String newStudent = "";
        do {
            System.out.print("Student: ");
            newStudent = input.nextLine();

            if (!newStudent.equals("")) {
                System.out.print("ID: ");
                Integer newID = input.nextInt();
                studentRoster.put(newID, newStudent);

                input.nextLine();
            }
        } while(!newStudent.equals(""));

        input.close();

        System.out.println("\nClass roster:");

        for (Map.Entry<Integer, String> student : studentRoster.entrySet()) {
            System.out.println(student.getValue() + "'s ID: " + student.getKey());
        }

        System.out.println("Number of students in roster: " + studentRoster.size());
    }
}