# isnormal() in C++ Programming

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In this article we will be discussing the working, syntax and examples of isnormal() function in C++ STL.

Isnormal() is a function which comes under the <cmath> header file. This function is used to check whether the given number is a normal number or not.

## What is a normal number?

A real number is known as a normal number if its base a number is neither zero, infinity, NAN or subnormal.

## Syntax

bool isnormal(float num);

## Parameters

The function accepts only one parameter which is num, of float type.

## Return value

It returns 0 or 1, if the number is a normal number then the function returns 1 else 0.

## Example

Input: isnormal(5.0);
Output: 1

Input: isnormal(0.0);
Output: 0

## Example

Live Demo

#include <bits/stdc++.h>
using namespace std;
int main() {
//For Float
cout<<"\n For Float : ";
float var_1 = 5.89F;
//when value is other than zero
cout<<"check for isnormal(5.89F) : "<<isnormal(var_1);
//when value is zero
var_1 = 0.0F;
cout<<"\ncheck for isnormal(0.0F) : "<<isnormal(var_1);
//when its a infinite value by dividing it with 0.0
var_1 = 2.2F;
cout<<"\ncheck for isnormal(2.2F/0.0F) : "<<isnormal(var_1/0.0F);
//For double
cout<<"\n\n For Double : ";
double var_2 = 5.89;
//when value is other than zero
cout<<"check for isnormal(5.89) : "<<isnormal(var_2);
//when value is zero
var_2 = 0.0;
cout<<"\ncheck for isnormal(0.0) : "<<isnormal(var_2);
//when its a infinite value by dividing it with 0.0
var_2 = 2.2;
cout<<"\ncheck for isnormal(2.2/0.0) : "<<isnormal(var_2/0.0);
//For Long double
cout<<"\n\n For Long Double : ";
long double var_3 = 5.89;
//when value is other than zero
cout<<"check for isnormal(5.89) : "<<isnormal(var_3);
//when value is zero
var_3 = 0.0;
cout<<"\ncheck for isnormal(0.0) : "<<isnormal(var_3);
//when its a infinite value by dividing it with 0.0
var_3 = 2.2;
cout<<"\ncheck for isnormal(2.2/0.0) : "<<isnormal(var_3/0.0);
return 0;
}

## Output

If we run the above code it will generate the following output −

For Float :
check for isnormal(5.89F) : 1
check for isnormal(0.0F) : 0
check for isnormal(2.2F/0.0F) : 0
For Double :
check for isnormal(5.89) : 1
check for isnormal(0.0) : 0
check for isnormal(2.2/0.0) : 0
For Long Double :
check for isnormal(5.89) : 1
check for isnormal(0.0) : 0
check for isnormal(2.2/0.0) : 0