/*
 *  =====================================================================
 *  Demonstrate "call-by-value" mechanism in function calls.
 * 
 *  Copyright (C) 1998 by Mark Austin and David Chancogne.
 *                                                                     
 *  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.
 * 
 *  Written By : M. Austin                                   January 1995
 *  =====================================================================
 */

#include <stdio.h>

int main( void ) {
int iVal  = 4, iReturnVal;
int tryChange( int iVal );     /* function declaration */

   /* [a] : Pass value of iVal  to tryChange() */

   printf("In main() : Passing value of iVal to \"tryChange\"\n" );
   iReturnVal = tryChange( iVal );                      
   printf("In main() : Now iVal       = %i\n", iVal ); 
   printf("                iReturnVal = %i\n", iReturnVal ); 

}

/*
 *  ========================================================
 *  tryChange() : Test program for changing parameters.
 *
 *  Input  : int iPassed -- integer passed to tryChange();
 *  Output : int iPassed -- modified value of iPassed.
 *  ========================================================
 */

int tryChange(int iPassed ) {
enum{ AddVal = 103 };

   /* [a] : Change a parameter that was passed by value */

   printf("In tryChange() : iPassed = %i\n", iPassed); 
   printf("In tryChange() : Adding %i to iPassed...\n", AddVal );
   iPassed += AddVal;
   printf("In tryChange() : Now iPassed = %i\n", iPassed); 

   return iPassed;
}