Question

What is the advantage of using bool variable in the code below instead of an int to set the value 1 or 0? What difference does it make?

#include<stdio.h>
int main(void)
{
    int p,d;
    _Bool isPrime;

    for ( p = 2; p <= 50; p++){
        isPrime = 1;

        for (d = 2; d < p; d++)
            if (p %d == 0)
                isPrime = 0;

        if (isPrime != 0)
            printf("%i ",p);
    }

    printf("\n");
    return 0;
}

Answer 1

It’s useful for making your intent clear. When you declare a variable as Bool_, it’s obvious it’s never supposed to have a value other than true and false.

A more conventional way to write your example code would be:

#include

int main(void)
{
    for (int p = 2; p <= 50; p++) {
        bool isPrime = true;

        for (int d = 2; d < p; d++) {
            if (p % d == 0) isPrime = false;
        }

        if (!isPrime) printf("%i ", p);
    }

    printf("\n");
    return 0;
}