# 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.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
``````

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