primeno-4.c

#include<stdio.h>

int isPrime(int n , int i)
{
    if(n < 2) return 0;
    if(n == 2) return 1;
    if(n % i == 0) return 0;
    if(i * i > n) return 1;
    isPrime(n, i + 1);
}

int main()
{
    int n;

    printf("Enter Value of n... ");
    scanf("%d", &n);

    if(isPrime(n, 2))
        printf("%d is a Prime Number.", n);
    else
        printf("%d is not a Prime Number.", n);
    return 0;
}