foo.cc: In function 'int main()':
foo.cc:11:21: warning: 'y' may be used uninitialized [-Wmaybe-uninitialized]
   11 |                 y=y * 10 + a;
      |                   ~~^~~~
foo.cc:6:15: note: 'y' was declared here
    6 |         int x,y;
      |               ^