Java Float isNaN Method

Introduction

In this lab, you will learn about Java isNaN(float v) method, which is used to check whether the float value passed is Not-a-Number(NaN) or not.

Create a Java file

Create a Java file named FloatIsNaN.java in the ~/project directory:

cd ~/project
touch FloatIsNaN.java

Define the main method

Add the following code to the main method:

public class FloatIsNaN {
    public static void main(String[] args) {

    }
}

Declare and define float variables

Declare and define float variables named f1, f2, f3, f4, and f5:

float f1 = 67.78f;
float f2 = 0f;
float f3 = -f1/0.0f;
float f4 = f2/0.0f;
float f5 = 0.0f/0.0f;

Test the Float.isNaN() method

Test whether the float values are NaN values by using the Float.isNaN() method:

System.out.println("The value is : " +Float.isNaN(f1)); //returns false for finite value
System.out.println("The value is : " +Float.isNaN(f2)); //returns false for infinite value
System.out.println("The value is : " +Float.isNaN(f3)); //returns false for infinite value
System.out.println("The value is : " +Float.isNaN(f4)); //returns true for NaN value
System.out.println("The value is : " +Float.isNaN(f5)); //returns true for NaN value

Compile and run the program

Save the changes to the file and compile the Java program using the javac command:

javac FloatIsNaN.java

Then, run the program using the java command:

java FloatIsNaN

Test the Float.isNaN() method with user input

Add the following code after step 3 to test the Float.isNaN() method with user input:

try {
    System.out.println("Enter the value");
    Scanner sc = new Scanner(System.in);
    float i = sc.nextFloat();
    boolean b = Float.isNaN(i);
    if(b == true) {
        System.out.println("Value is NaN");
    } else {
        System.out.println("Value is non NaN");
    }
} catch(Exception e) {
    System.out.println("Invalid Input");
}

Compile and run the program

Save the changes to the file and compile the Java program using the javac command:

javac FloatIsNaN.java

Then, run the program using the java command:

java FloatIsNaN

Test the Float.isNaN() method live

You can also test the Float.isNaN() method live with the following example:

import java.lang.Float;
import java.util.Scanner;

public class FloatIsNaN {
    public static void main(String[] args) {
        try {
            System.out.println("Enter the value");
            Scanner sc = new Scanner(System.in);
            float i = sc.nextFloat();
            boolean b = Float.isNaN(i);
            if(b == true) {
                System.out.println("Value is NaN");
            } else {
                System.out.println("Value is non NaN");
            }
        } catch(Exception e) {
            System.out.println("Invalid Input");
        }
    }
}

Compile and run the program

Save the changes to the file and compile the Java program using the javac command:

javac FloatIsNaN.java

Then, run the program using the java command:

java FloatIsNaN

Summary

In this lab, you have learned the following:

• Java isNaN(float v) method is used to check whether a given float value is a NaN value or not.
• The isNaN() method returns the boolean value true for NaN values and false for non-NaN values.
• You can test the isNaN() method by declaring and defining float variables or by taking user input.
• You can also test the isNaN() method live with the example provided in the lab.

Good job!