C++ Math isinf()

The function determines whether the number is infinite or not. It can be positive or negative infinite. If the number is infinite, it returns 1 otherwise 0.

Syntax

Suppose a number is 'x'. Syntax would be:

bool isinf(float x);
bool isinf(double x);
bool isinf(long double x);
bool isinf(integral x);

Parameter

x: It is a floating point value.

Return value

Parameter(x)	Return value
Finite value	Infinite value
0	1

Example 1

Let's see the simple example when the value of x is 1.0/0.0.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
    float x=1.0/0.0;
    cout<<"value of x is : "<<x<<'\n';
    cout<<"isinf(x) : "<<isinf(x);
    return 0;
}

Output:

value of x is : inf
isinf(x) : 1

In this example, isinf() function determines that the value of x is infinite. Therefore, it returns 1.

Example 2

Let's see the simple example when the value of x is 4.

#include <iostream>
#include<math.h>
using namespace std;
int main()
{
    int x=4;
    cout<<"value of x is : "<<x<<'\n';
    cout<<"isinf(x) : "<<isinf(x);
    return 0;
}

Output: