Prime number program in c using recursion

source code:

#include<stdio.h>

int isPrime(int,int);

int main()

{

    int num,prime;

    printf("Enter a positive number: ");

    scanf("%d",&num);

    prime = isPrime(num,num/2);

   if(prime==1)

        printf("%d is a prime number",num);

   else

      printf("%d is not a prime number",num);

   getch();

   return 0;

}

int isPrime(int num,int i)

{

    if(i==1){

        return 1;

    }else{

       if(num%i==0)

         return 0;

       else

         isPrime(num,i-1);

    }

}