programming-examples/c/Basic/C Program to Find whether a Number is Prime or Not using Recursion.c

/*
 * C Program to find whether a Number is Prime or Not using Recursion
 */
#include <stdio.h>

int primeno(int, int);

int main()
{
    int num, check;
    printf("Enter a number: ");
    scanf("%d", &num);
    check = primeno(num, num / 2);
    if (check == 1)
        {
            printf("%d is a prime number\n", num);
        }
    else
        {
            printf("%d is not a prime number\n", num);
        }
    return 0;
}

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