Tuesday, 3 November 2015

Comparator Demo Using TreeSet

import java.util.*;
class Student
{
	int rollno;
	String name;
	String phone;
}

class MyComp implements Comparator {
	public int compare(Object o1, Object o2) {
		Student s1, s2; 
		s1 = (Student) o1; 
		s2 = (Student) o2; 
		int c;
		if(s1.rollno < s2.rollno)
			c = -1;
		else if (s1.rollno > s2.rollno)
			c = 1;
		else
			c = 0;
		return c;
	} 
}

class MyComp1 implements Comparator {
	public int compare(Object o1, Object o2) {
		Student s1, s2; 
		s1 = (Student) o1; 
		s2 = (Student) o2; 
		int c;
		int x = (s1.name).compareTo(s2.name);
		return x;
	} 
}
class CompDemo {
	public static void main(String args[]) {
		// Create a tree set.
		TreeSet ts = new TreeSet(new MyComp1()); 
		// Add elements to the tree set.
		Student s1 = new Student();
		s1.rollno = 1; s1.name = "Rahul"; s1.phone = "2590381";

		Student s2 = new Student();
		s2.rollno = 5; s2.name = "Devesh"; s2.phone = "9829059033";

		Student s3 = new Student();
		s3.rollno = 3; s3.name = "Rakesh"; s3.phone = "2590381";

		Student s4 = new Student();
		s4.rollno = 2; s4.name = "Manohar"; s4.phone = "2590381";

		Student s5 = new Student();
		s5.rollno = 4; s5.name = "Prateek"; s5.phone = "2590381";

		ts.add(s1); 
		ts.add(s2); 
		ts.add(s3); 
		ts.add(s4); 
		ts.add(s5); 
		// Display the elements.
		Iterator<Student> i = ts.iterator();
		while(i.hasNext()) {
			Student s = i.next();
			System.out.println(s.rollno +", "+ s.name + ", " +s.phone);
		}
	}
}

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