Prime Number or Not

//PROGRAM TO CHECK WHETHER THE GIVEN NUMBER IS PRIME OR NOT
#include
#include
int check(int);
void main()
{
int num,ret;
printf("Enter the number : ");
scanf("%d",&num);
ret=check(num);
if(ret==1)
printf("%d is not Prime\n",num);
else if(ret==0)
printf("%d is Prime\n",num);
else
printf("It is neither prime nor composite\n");
getch();
}

int check(int n)
{
int i;
if(n==0)
return 1;
if(n==1)
return -1;
for(i=2;i {
if(n%i==0)
return 1;
}
return 0;
}