recursion c prime number

#include <stdio.h>

int isPrime(int num, int i);

int main() {
    int num;

    printf("Enter a positive integer: ");
    scanf("%d", &num);

    if (num > 1) {
        if (isPrime(num, num / 2) == 1)
            printf("%d is a prime number.\n", num);
        else
            printf("%d is not a prime number.\n", num);
    } else {
        printf("Enter a positive integer greater than 1.\n");
    }

    return 0;
}

int isPrime(int num, int i) {
    if (i == 1)
        return 1;
    else {
        if (num % i == 0)
            return 0;
        else
            return isPrime(num, i - 1);
    }
}