/in/foo.c: In function 'main':
/in/foo.c:31:5: warning: 'days' may be used uninitialized [-Wmaybe-uninitialized]
   31 |     printf("%d\n", days);
      |     ^~~~~~~~~~~~~~~~~~~~
/in/foo.c:5:22: note: 'days' was declared here
    5 |     int month, year, days;
      |                      ^~~~