80-qsort.c 1.4 KB

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  1. /* -*-comment-start: "//";comment-end:""-*-
  2. * GNU Mes --- Maxwell Equations of Software
  3. * Copyright © 2017 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
  4. *
  5. * This file is part of GNU Mes.
  6. *
  7. * GNU Mes is free software; you can redistribute it and/or modify it
  8. * under the terms of the GNU General Public License as published by
  9. * the Free Software Foundation; either version 3 of the License, or (at
  10. * your option) any later version.
  11. *
  12. * GNU Mes is distributed in the hope that it will be useful, but
  13. * WITHOUT ANY WARRANTY; without even the implied warranty of
  14. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15. * GNU General Public License for more details.
  16. *
  17. * You should have received a copy of the GNU General Public License
  18. * along with GNU Mes. If not, see <http://www.gnu.org/licenses/>.
  19. */
  20. #include <mes/lib.h>
  21. #include <string.h>
  22. int
  23. compare_int (void *a, void *b)
  24. {
  25. eputs ("compare: ");
  26. eputs (itoa (*(int *) a));
  27. eputs (" <? ");
  28. eputs (itoa (*(int *) b));
  29. eputs (" => ");
  30. eputs (itoa (*(int *) a - *(int *) b));
  31. eputs ("\n");
  32. return *(int *) a - *(int *) b;
  33. }
  34. int
  35. main ()
  36. {
  37. int lst[6] = { 0, 5, 4, 3, 2, -1 };
  38. qsort (lst, 6, sizeof (int), compare_int);
  39. for (int i = 0; i < 6; i++)
  40. {
  41. eputs (itoa (i));
  42. eputs (":");
  43. eputs (itoa (lst[i]));
  44. eputs ("\n");
  45. }
  46. if (lst[0] != -1)
  47. return 1;
  48. if (lst[5] != 5)
  49. return 2;
  50. return 0;
  51. }