GPA Calculator

import java.util.Scanner;

public class GPACalculator {

    public static void main(String []args) {

        Scanner scan = new Scanner(System.in);
        int numberOfStudents = 1;
        double studentGPA;
        int numberOfGPABelowTwo = 0;

        System.out.println();

        do {

            System.out.print("Enter student GPA for Student #" + numberOfStudents + " or (-1) to " +
                    "exit" + ": ");
            studentGPA = scan.nextDouble();

            while (studentGPA < -1) {
                System.out.println("Invalid GPA value.");
                System.out.print("Enter student GPA for Student #" + numberOfStudents + ": ");
                studentGPA = scan.nextDouble();
            }

            if (studentGPA <= 2.0 && studentGPA != -1) {
                numberOfGPABelowTwo++;
            }
            numberOfStudents++;

        } while (studentGPA != -1);

        System.out.printf("%,d %s", numberOfGPABelowTwo, numberOfGPABelowTwo > 1 ? "students " +
                "have warnings." : "student has a warning.");

    } // end main
} // end class