manual/examples/add.c

   1 /* Example of a Variadic Function
   2    Copyright (C) 1991-2019 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU General Public License
   6    as published by the Free Software Foundation; either version 2
   7    of the License, or (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, see <https://www.gnu.org/licenses/>.
  16 */
  17
  18 #include <stdarg.h>
  19 #include <stdio.h>
  20
  21 int
  22 add_em_up (int count,...)
  23 {
  24   va_list ap;
  25   int i, sum;
  26
  27   va_start (ap, count);         /* Initialize the argument list. */
  28
  29   sum = 0;
  30   for (i = 0; i < count; i++)
  31     sum += va_arg (ap, int);    /* Get the next argument value. */
  32
  33   va_end (ap);                  /* Clean up. */
  34   return sum;
  35 }
  36
  37 int
  38 main (void)
  39 {
  40   /* This call prints 16. */
  41   printf ("%d\n", add_em_up (3, 5, 5, 6));
  42
  43   /* This call prints 55. */
  44   printf ("%d\n", add_em_up (10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
  45
  46   return 0;
  47 }