Published Oct 31, 2022Updated Dec 21, 2022
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The isfinite() function returns a value telling whether the argument has a finite value.



The x parameter is finite if it is a floating-point number that is neither infinite nor NaN (e.g., division by zero, square root of a negative value).

If x is finite, the isfinite() function will return a non-zero value for true. Otherwise, it will return zero for false.


The following example uses the isfinite() function to check whether 5.0 is finite:

#include <iostream>
#include <cmath>
int main() {
int result;
result = std::isfinite(5.0);
if (result == 0) {
std::cout << "Not finite" << "\n";
else {
std::cout << "Is finite" << "\n";
// Output: Is finite

Codebyte Example

The following example is runnable and features a case where running the isfinite() function where the returns false and the value is not finite:


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