Java

OOP GUIDE / WORK

STUDENT CLASS

Topics

• Implementing the Comparable interface
• Implementing the compareTo method
• Sorting object arrays with Comparable

TASK – PART 1 – SETUP

No solution required.

TASK – PART 2 – IMPLEMENTING COMPARABLE

Here is my solution:

public class Student implements Comparable

{

public String lastName;

public String firstName;

public int grade;

public String school;

public Student()

{

String[] lastNames = {"Smith", "Do", "Bardot", "Lu", "Green", "Lowe", "Bacon", "Zoom", "Gravy", "TwoShoes", "Monroe", "Hope", "West", "Lopez", "Gray"};

lastName = lastNames[(int)(Math.random() * lastNames.length)];

String[] firstNames = {"Jimmy", "June", "Abbott", "Luna", "Harry", "Moon", "Lea", "Kayla", "Aryan", "Grace", "Drake", "Kiana", "Burt", "Amitoj", "Xavier", "Shaun", "Mary"};

firstName = firstNames[(int)(Math.random() * firstNames.length)];

grade = (int)(Math.random() * 4) + 9;

String[] schools = {"Lockerby", "Confed", "Lasalle", "Lo-Ellen"};

school = schools[(int)(Math.random() * schools.length)];

}

public String toString()

{

return grade + " " + firstName + " " + lastName + " (" + school + ")";

}

@Override

public int compareTo(Object o)

{

Student other = (Student)o;

if (this.grade < other.grade)

return -1;

else if (this.grade == other.grade)

{

return 0;

}

else //this.grade > other.grade

{

return 1;

}

}

}

import java.util.Arrays;

public class StudentTester

{

public static void main(String[] args)

{

Student[] stews = new Student[20];

//Create students

for (int i=0; i<stews.length; i++)

{

stews[i] = new Student();

}

//Output students

for (int i=0; i<stews.length; i++)

{

System.out.println(stews[i]);;

}

Arrays.sort(stews);

System.out.println("=====");

//Output students

for (int i=0; i<stews.length; i++)

{

System.out.println(stews[i]);;

}

}

}