#include <iostream>
using std::cout;
using std::endl;

#include <iomanip>
using std::setw;

unsigned long factorial( unsigned long ); // function prototype

int main()
{
   for ( int counter = 0; counter <= 50; counter++ )
      cout << setw( 2 ) << counter << "! = " << factorial( counter ) << endl;

   return 0;
}
unsigned long factorial( unsigned long number )
{
   if ( number <= 1 )
      return 1;
   else
      return number * factorial( number - 1 );
}