Fibonacci numbers

#include "iostream.h"
#include "conio.h"

// sequence is 0, 1, 1, 2, 3, 5, 8, 13, ...

int fib (int i) {
int pred, result, temp;

pred = 1;
result = 0;

while (i > 0) {
temp = pred + result;
result = pred;
pred = temp;
i = i-1;
}
return(result);
}

void main () {
int n;
cout << "Enter a natural number: ";
cin >> n;
while (n < 0) {
cout << "Please re-enter: ";
cin >> n;
}
cout << "fib(" << n << ") = " << fib(n) << endl;

}