Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Checking if a double (or float) is NaN in C++
To check whether a floating point or double number is NaN (Not a Number) in C++, we can use the isnan() function. The isnan() function is present into the cmath library. This function is introduced in C++ version 11. So From C++11 next, we can use this function.
Example
#include <cmath>
#include <iostream>
using namespace std;
main() {
if(isnan(sqrt(30))) { //square root of 30 is a floating point number
cout << "Square root of 30 is not a number" <<endl;
} else {
cout << "Square root of 30 is a number" <<endl;
}
if(isnan(sqrt(-30))) { //square root of -30 is an imaginary number
cout << "Square root of -30 is not a number" <<endl;
} else {
cout << "Square root of -30 is a number" <<endl;
}
}Output
Square root of 30 is a number Square root of -30 is not a number
Updated on: 30-Jul-2019
12K+ Views
Advertisements