Question

Assume that a total order is not defined on a set of

objects created from a class. What method do you need to write, to
implement the Comparable interface?

Answer 1

To implement the Comparable interface when a total order is not defined on a set of objects, you need to write the compareTo method that compares two objects and returns a negative integer, zero, or a positive integer based on their relationship. An example implementation of Comparable on a Person class is provided.

Step-by-step explanation:

When implementing the Comparable interface on a class in which a total order is not defined on a set of objects, you need to write the compareTo method. This method is responsible for comparing two objects and returning a negative integer, zero, or a positive integer depending on whether the current object is less than, equal to, or greater than the specified object, respectively.

For example, let's say we have a class called Person and we want to implement the Comparable interface:

public class Person implements Comparable<Person> {
private String name;
private int age;

// Constructor and other methods here

public int compareTo(Person otherPerson) {
return this.age - otherPerson.age;
}
}

In this case, the compareTo method compares the age of two Person objects and returns a negative value if the current person is younger, zero if they have the same age, and a positive value if the current person is older.