# Kotlin isNaN()

## Kotlin isNaN()

In Kotlin, the `isNaN()` function is used to check if a floating-point number is “Not a Number” (NaN).

This function is helpful for handling special cases in mathematical calculations where an operation may result in an undefined or non-numeric value.

In this tutorial, we’ll explore the syntax of the `isNaN()` function and provide examples of its usage in Kotlin.

## Syntax

The syntax of the `isNaN()` function is:

``````fun Double.isNaN(): Boolean
fun Float.isNaN(): Boolean``````

The function returns `true` if the number is `NaN`, and `false` otherwise.

## Examples

### 1. Using isNaN() to Check for NaN

In this example, we’ll use `isNaN()` to check if a result from a mathematical operation is NaN.

Kotlin Program

``````fun main() {
val result1 = 10.0 / 5          //2
val result2 = 10.0 / 0          //Infinity
val result3 = Math.sqrt(-1.0)   //NaN

println("result1 : \$result1")
println("result2 : \$result2")
println("result3 : \$result3")

println("Is result1 NaN? \${result1.isNaN()}")
println("Is result2 NaN? \${result2.isNaN()}")
println("Is result3 NaN? \${result3.isNaN()}")
}``````

Output

``````result1 : 2.0
result2 : Infinity
result3 : NaN
Is result1 NaN? false
Is result2 NaN? false
Is result3 NaN? true``````

In this example, we perform three mathematical operations that result in a number, Infinity, and NaN respectively. The `isNaN()` function is used to check if the results are NaN, and the outcome is printed.

## Summary

In this tutorial, we’ve covered the `isNaN()` function in Kotlin, its syntax, and how to use it for checking if a double-precision floating-point number is NaN.