foo.c: In function 'main':
foo.c:16:3: warning: statement with no effect [-Wunused-value]
   for (h ; h > 23; h - 24)h = h - 24;
   ^~~
foo.c:16:22: warning: statement with no effect [-Wunused-value]
   for (h ; h > 23; h - 24)h = h - 24;
                    ~~^~~~
foo.c:20:3: warning: statement with no effect [-Wunused-value]
   for (m; m > 59; m - 60)m = m - 60;
   ^~~
foo.c:20:21: warning: statement with no effect [-Wunused-value]
   for (m; m > 59; m - 60)m = m - 60;
                   ~~^~~~
foo.c:24:3: warning: statement with no effect [-Wunused-value]
   for (s; s > 59; s - 60)s = s - 60;
   ^~~
foo.c:24:21: warning: statement with no effect [-Wunused-value]
   for (s; s > 59; s - 60)s = s - 60;
                   ~~^~~~
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d\n%d", &h, &m, &s,&num);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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