How do I get signum function of a number?

The code below show you how to get the signum function of a number using the Math.signum() static method call. This method extracts the sign of a real number. If you have a number of x the signum function of x is -1 if x < 0; 0 if x = 0 and 1 if x > 0.

package org.kodejava.example.math;

public class SignumExample {

    public static void main(String[] args) {
        Double zero = 0.0D;
        Double negative = -25.0D;
        Double positive = 15.0D;

        //
        // Get the signum function of value of a number.
        // It returns:
        // * 0 if the value is zero.
        // * 1.0 if value is greater than zero.
        // * -1.0 if value is less than zero.
        //
        double sign1 = Math.signum(zero);
        double sign2 = Math.signum(negative);
        double sign3 = Math.signum(positive);

        //
        // For floating-point value
        //
        float sign4 = Math.signum(zero.floatValue());
        float sign5 = Math.signum(negative.floatValue());
        float sign6 = Math.signum(positive.floatValue());

        System.out.println("In double:");
        System.out.println("Signum of " + zero + " is " + sign1);
        System.out.println("Signum of " + negative + " is " + sign2);
        System.out.println("Signum of " + positive + " is " + sign3);

        System.out.println("In float:");
        System.out.println("Signum of " + zero + " is " + sign4);
        System.out.println("Signum of " + negative + " is " + sign5);
        System.out.println("Signum of " + positive + " is " + sign6);
    }
}

Here is the output of the program:

In double:
Signum of 0.0 is 0.0
Signum of -25.0 is -1.0
Signum of 15.0 is 1.0
In float:
Signum of 0.0 is 0.0
Signum of -25.0 is -1.0
Signum of 15.0 is 1.0
Wayan Saryada

Wayan Saryada

A programmer, runner, recreational diver, currently living in the island of Bali, Indonesia. Mostly programming in Java, creating web based application with Spring Framework, JPA, etc. If you need help on Java programming you can hire me on Fiverr.
Wayan Saryada

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