programmingfaster.com

#include <stdio.h>
#include<conio.h>
int primeno(int, int);
int main()
{
    int num,c;
    printf("Enter a number: ");
    scanf("%d", &num);
    c= primeno(num, num / 2);
    if (c == 1)
    {        printf("%d is a prime number\n", num);}
    else
    {printf("%d is not a prime number\n", num);}
    getch();
    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);}
    }
}