foo.c: In function 'main':
foo.c:4:1: warning: 'month' is used uninitialized in this function [-Wuninitialized]
    4 | switch (month)
      | ^~~~~~
foo.c:6:21: warning: 'year' may be used uninitialized in this function [-Wmaybe-uninitialized]
    6 |     case 2:if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))
      |                ~~~~~^~~~~

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