What is INFINITY In C?

INFINITY is a macro constant defined in the <math.h> library, and programmers use it to perform mathematical comparisons in C.

#include <math.h>

Example

C allows us to define INFINITY as positive INFINITY or negative INFINITY.

The snippet below shows how positive or unsigned INFINITY may be defined, and subsequently used in a mathematical comparison:

#include <math.h>
#include <stdio.h>
int main()
{
    double pos_inf = INFINITY;
    double number = 112421421412124;
    if (number < pos_inf)
    {
        printf("INFINITY wins!");  
    }
    return 0;
}

Negative INFINITY can be defined as demonstrated in the code below:

#include <math.h>
#include <stdio.h>
int main()
{
    //Note that to define negative inifinity, we put '-' before INFINITY
    double pinf = -INFINITY;
    double neg_ninf = 112421421412124;
    if ( neg_ninf < pinf)
    {
        printf("INFINITY wins!");  
    }
    else if (neg_ninf > pinf)
    {
        printf("INFINITY loses !");
    }
    return 0;
}

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