Double.compareTo() Method in Java with Examples

The java.lang.Double.compareTo() is a built-in method in java that compares two Double objects numerically. This method returns 0 if this object is equal to the argument object, it returns less than 0 if this object is numerically less than the argument object and a value greater than 0 if this object is numerically greater than the argument object.

Syntax:

public int compareTo(Object obj)

Parameter: The method accepts one parameter.
obj – The object which is to be compared to.

Return Values: The function can return three values:

• equal to 0: Object is equal to the argument object
• less than 0: Object is less than the argument object
• greater than 0: Object is greater than the argument object

Below programs illustrates the working of java.lang.Double.compareTo() method:

Program 1: When both objects are different.

// Java program to demonstrate
// of java.lang.Double.compareTo() method
import java.lang.Math;

class Gfg1 {

    // Driver code
    public static void main(String args[])
    {

        // When two objects are different
        Double obj1 = new Double(124);
        Double obj2 = new Double(167);
        int compareValue = obj1.compareTo(obj2);

        if (compareValue == 0)
            System.out.println("object1 and object2 are equal");
        else if (compareValue < 0)
            System.out.println("object1 is less than object2");
        else
            System.out.println("object1 is greater than object2");
    }
}

Output:

object1 is less than object2

Program 2: When no argument is passed.

// Java program to demonstrate
// of java.lang.Double.compareTo() method
import java.lang.Math;

class Gfg1 {

    // Driver code
    public static void main(String args[])
    {
        // When no argument is passed
        Double obj1 = new Double(124);
        Double obj2 = new Double(167);

        int compareValue = obj1.compareTo();

        if (compareValue == 0)
            System.out.println("object1 and object2 are equal");
        else if (compareValue < 0)
            System.out.println("object1 is less than object2");
        else
            System.out.println("object1 is greater than object2");
    }
}

Output:

prog.java:14: error: method compareTo in class Double 
cannot be applied to given types;
        int compareValue = obj1.compareTo();
                               ^
  required: Double
  found: no arguments
  reason: actual and formal argument lists differ in length
1 error

Program 3: When anything other than object is passed as an argument.

// Java program to demonstrate
// of java.lang.Double.compareTo() method
import java.lang.Math;

class Gfg1 {

    // Driver code
    public static void main(String args[])
    {

        // When anything other than object
        // argument is passed
        Double obj1 = new Double(124);

        int compareValue = obj1.compareTo("gfg");

        if (compareValue == 0)
            System.out.println("object1 and object2 are equal");
        else if (compareValue < 0)
            System.out.println("object1 is less than object2");
        else
            System.out.println("object1 is greater than object2");
    }
}

Output:

prog.java:15: error: incompatible types: String cannot be converted to Double
        int compareValue = obj1.compareTo("gfg");
                                          ^
Note: Some messages have been simplified; recompile with 
-Xdiags:verbose to get full output
1 error