Question

Write a Java program that sorts an array of “Student” in an aescending order of their “last names”. The program should be able to apply (selection sort):

Student [] studs = new Student[8];

s[0] = new Student("Saoud", "Mohamed", 3.61);

s[1] = new Student("Abdelkader", "Farouk", 2.83);

s[2] = new Student("Beshr" , "Alsharqawy", 1.99);

s[3] = new Student("Nader", "Salah", 3.02);

s[4] = new Student("Basem", "Hawary", 2.65);

s[5] = new Student("Abdullah", "Babaker", 2.88);

s[6] = new Student("Abdelaal", "Khairy", 3.13);

s[7] = new Student("Mohamedain", "Marsily", 4.00);

Answer 1

I have written the required method along with class definition

Student.java

class Student {
    String firstName, lastName;
    double gpa;

    public Student(String fn, String ln, double g) {
        this.firstName = fn;
        this.lastName = ln;
        this.gpa = g;
    }

    /**
     * function to sort the student by the last name
     * @param students
     */
    public static void sortByLastName(Student[] students) {
        for (int i = 0; i < students.length; i++) {
            // index for selecting entity
            int index = i;
            for (int j = i + 1; j < students.length; j++) {
                // comparing based on last name
                if (students[j].lastName.compareTo(students[index].lastName) < 1) {
                    index = j;
                }
            }
            // swapping the values
            Student temp = students[index];
            students[index] = students[i];
            students[i] = temp;
        }
    }

    @Override
    public String toString() {
        return String.format("%s, %s,  %.2f\n", this.firstName, this.lastName, this.gpa);
    }

    public static void main(String[] args) {
        Student[] students = new Student[8];
        students[0] = new Student("Saoud", "Mohamed", 3.61);
        students[1] = new Student("Abdelkader", "Farouk", 2.83);
        students[2] = new Student("Beshr", "Alsharqawy", 1.99);
        students[3] = new Student("Nader", "Salah", 3.02);
        students[4] = new Student("Basem", "Hawary", 2.65);
        students[5] = new Student("Abdullah", "Babaker", 2.88);
        students[6] = new Student("Abdelaal", "Khairy", 3.13);
        students[7] = new Student("Mohamedain", "Marsily", 4.00);
        // calling method for sorting the students
        sortByLastName(students);
        // printing the students
        for (Student s : students) {
            System.out.println(s);
        }
    }
}

// OUT

Please do let me know if u have any concern...