// Recursive fibonacci function.
#include
<iostream>
unsigned long
fibonacci( unsigned long ); // function prototype
int main()
{
unsigned long result,
number;
// obtain integer from user
cout << "Enter
an integer: ";
cin >> number;
// calculate fibonacci value for number
input by user
result = fibonacci( number );
// display result
cout << "Fibonacci("
<< number << ") = " << result << endl;
return 0;
// indicates successful termination
}
The Fibonacci numbers get large very quickly, and
are all non-negative integers. Thus, we use the
unsigned long data
type.