Check for prime number in Objective-C

#import <Foundation/Foundation.h>

int isPrime(int n)
{
int i;
if(n==1||n==2)
return 0;
for(i=3;i<=n/2;i++)
if(n%i==0)
return 0;
return 1;
}

int main (int argc, const char * argv[])
{
   NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
   int i;
   for(i=1;i<=100;i++)
   {
   if(isPrime(i)==1)
    NSLog (@"%d is Prime number,",i);
   else
    NSLog (@"%d is not Prime number,",i);
   }
 [pool drain];
   return 0;
}