glibc/manual/examples/add.c

/* Example of a Variadic Function
   Copyright (C) 1991-2021 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; either version 2
   of the License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, see <https://www.gnu.org/licenses/>.
*/

#include <stdarg.h>
#include <stdio.h>

int
add_em_up (int count,...)
{
  va_list ap;
  int i, sum;

  va_start (ap, count);		/* Initialize the argument list. */

  sum = 0;
  for (i = 0; i < count; i++)
    sum += va_arg (ap, int);	/* Get the next argument value. */

  va_end (ap);			/* Clean up. */
  return sum;
}

int
main (void)
{
  /* This call prints 16. */
  printf ("%d\n", add_em_up (3, 5, 5, 6));

  /* This call prints 55. */
  printf ("%d\n", add_em_up (10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10));

  return 0;
}