public int compareTo(Student to) {
        if (this.getCgpa() != to.getCgpa()) {
            return (new Double(to.getCgpa())).compareTo(this.getCgpa());
        }
        if (this.getFname() != to.getFname()) {
            return this.getFname().compareTo(to.getFname());
        }
        return (new Integer(this.getId())).compareTo(to.getId());
    }