public class staff implements Comparable {
    private String name;
    private int age;
    private String salary;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getSalary() {
        return salary;
    }

    public void setSalary(String salary) {
        this.salary = salary;
    }

    @Override
    public int compareTo(Object obj) {
        if (obj instanceof staff) {
            staff st = (staff) obj;
            return st.salary - this.salary;
        }
        return -1;
    }
}

//private String salary;
private double salary;

    //public String getSalary() {
    public double getSalary() {
        return salary;
    }

    //public void setSalary(String salary) {
    public void setSalary(double salary) {
        this.salary = salary;
    }