foo.cc: In function ‘int main()’:
foo.cc:54:15: warning: ‘n’ may be used uninitialized [-Wmaybe-uninitialized]
   54 |         cout<<n;
      |               ^
foo.cc:5:19: note: ‘n’ was declared here
    5 |         int y,m,d,n;
      |                   ^