/*
 *  ======================================================================== 
 *  prog_recursion.c : compute five factorial (5!) with recursive algorithm.
 *
 *  Copyright (C) 1994-96 by Mark Austin and David Mazzoni.
 *                                                                     
 *  This software is provided "as is" without express or implied warranty.
 *  Permission is granted to use this software on any computer system,
 *  and to redistribute it freely, subject to the following restrictions:
 * 
 *  1. The authors are not responsible for the consequences of use of
 *     this software, even if they arise from defects in the software.
 *  2. The origin of this software must not be misrepresented, either
 *     by explicit claim or by omission.
 *  3. Altered versions must be plainly marked as such, and must not
 *     be misrepresented as being the original software.
 *  4. This notice is to remain intact.
 *  ======================================================================== 
 */

#include <stdio.h>                        /* Include i/o declarations  */

int main( void ) {               
unsigned long ulFact;                     /* Holds the factorial       */
unsigned long Factorial(int iVal);        /* Function declaration      */
  
     ulFact = Factorial( 5 );
     printf( "Factorial(%2d) = %8lu\n", 5, ulFact );
}

/*
 *  =================================================================
 *  Use recursive algorithm to compute factorial of an integer
 *  
 *  Input:  int iN  -- calculate the factorial of iN using recursion.
 *  =================================================================
 */

unsigned long Factorial( int iN ) {

  if( iN <= 1 )                       /* termination condition      */
    return 1;
  else
    return iN * Factorial( iN - 1 );  /* recursively call factorial */

}