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);
    }
}

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