#include <stdio.h>

int f_by_value(int arg)
{
 int calc_res = 0;
 calc_res = arg+1;
 return calc_res; 
}

void f_by_reference(int *arg_address)
{
 int calc_res;
 calc_res = *arg_address+1;
 *arg_address = calc_res; 
}

void main()
{
 int i;
 int return_value;

 /* inialize values */
 i = 10;
 return_value = 999;

 printf(" before f_by_value():     (i, return_value) is  (%d, %d)\n", i, return_value);

 /* call by value */
 return_value = f_by_value(i);

 printf(" after  f_by_value():     (i, return_value) is  (%d, %d)\n\n", i, return_value);

 /* re-inialize values */
 i = 10;
 return_value = 999;

 printf(" before f_by_reference(): (i, return_value) is  (%d, %d)\n", i, return_value);

 /* call by reference */
 f_by_reference(&i);

 printf(" after  f_by_reference(): (i, return_value) is  (%d, %d)\n", i, return_value);
}