You can make it smaller. When I make programs I don't add the line do{ and the space above the int main is not required. It's just to make it look good. And I don't really understand the i!=0 either. I usually use namespace Std and the system pause.

Code:
#include <iostream>
using namespace std;
int main ()
{
  int i;
    cout << "Type a number (0 to exit): \n";
    cin >> i;
    if ((i%2)!=0) cout << "Number is odd.\n";
  else cout << "Number is even.\n";   
  while (i!=0);
  return 0;
 }