class Student implements Comparable<Student> {
String id;
String name;
Double cgpa;
public Student(String studentId, String studentName, double studentCGPA) {
id = studentId;
name = studentName;
cgpa = studentCGPA;
}
public String toString() {
return " \n " + id + " \t " + name + " \t " + cgpa;
}
public int compareTo(Student that) {
return this.id.compareTo(that.id);
}
}
Then, you may add another class entitled ComparatorTest2 as follows :
import java.util.Arrays;
import java.util.Comparator;
class CGPAComparator implements Comparator<Student> {
public int compare(Student s1, Student s2) {
return (s1.cgpa.compareTo(s2.cgpa));
}
}
class ComparatorTest2 {
public static void main(String []args) {
Student []students = { new Student("cs011", "Lennon ", 3.1),
new Student("cs021", "McCartney", 3.4),
new Student("cs012", "Harrison ", 2.7),
new Student("cs022", "Starr ", 3.7) };
System.out.println("Before sorting by CGPA ");
System.out.println("Student-ID \t Name \t CGPA (for 4.0) ");
System.out.println(Arrays.toString(students));
Arrays.sort(students, new CGPAComparator());
System.out.println("After sorting by CGPA");
System.out.println("Student-ID \t Name \t CGPA (for 4.0) ");
System.out.println(Arrays.toString(students));
}
}
If you run this program you would get the following output :
Before sorting by CGPA
Student-ID Name CGPA (for 4.0)
[
cs011 Lennon 3.1,
cs021 McCartney 3.4,
cs012 Harrison 2.7,
cs022 Starr 3.7]
After sorting by CGPA
Student-ID Name CGPA (for 4.0)
[
cs012 Harrison 2.7,
cs011 Lennon 3.1,
cs021 McCartney 3.4,
cs022 Starr 3.7]
That's it, as you might have noticed, the students array was sorted according to cgpa field.
