import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class HashMapPractice {
    public static void main(String[] args) {
    HashMap<String, Double> students = new HashMap<>();
    Scanner input = new Scanner(System.in);
    String newStudent;

         System.out.println("Enter your students (or ENTER to finish):");

    // Get student names and grades
         do

    {

        System.out.print("Student: ");
        newStudent = input.nextLine();

        if (!newStudent.isEmpty()) {
            System.out.print("Id: ");
            Double newId = input.nextDouble();
            students.put(newStudent, newId);

            // Read in the newline before looping back
            input.nextLine();
        }

    } while(!newStudent.isEmpty());

    // Print class roster
         System.out.println("\nClass roster:");
    double sum = 0.0;

         for(
    Map.Entry<String, Double> student :students.entrySet())

    {
        System.out.println(student.getKey() + " (" + student.getValue() + ")");
        sum += student.getValue();
    }

    double avg = sum / students.size();
         System.out.println("Average grade: "+avg);
}
}