Fact on C Program

#include 

int fact (int i)

 {

  int result = 1;

  while (i > 0)

 {

    result = result * i;

    i = i-1;

  }

  return(result);

}

int main () 

{

  int n;

  cout << "Enter a natural number: ";

  cin >> n;

  while (n < 0)

 {

    cout << "Please re-enter: ";

    cin >> n;

  }

  cout << n << "! = " << fact(n) << endl;

  return(0);

}