foo.cc: In function ‘int main()’:
foo.cc:36:15: warning: ‘allday’ may be used uninitialized [-Wmaybe-uninitialized]
   36 |         cout<<allday<<endl;
      |               ^~~~~~
foo.cc:6:33: note: ‘allday’ was declared here
    6 |         int year,month,leap,day,allday;
      |                                 ^~~~~~