foo.c: In function 'main':
foo.c:33:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d", &y1, &m1, &d1);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.c:34:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d %d", &y1, &m1, &d1);
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.c:35:15: warning: 'y2' is used uninitialized in this function [-Wuninitialized]
  int result = day(y2, m2, d2)-day(y1, m1, d1);
               ^~~~~~~~~~~~~~~
foo.c:35:15: warning: 'm2' is used uninitialized in this function [-Wuninitialized]
foo.c:35:15: warning: 'd2' is used uninitialized in this function [-Wuninitialized]

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