foo.cc: In function ‘int main()’:
foo.cc:12:30: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   12 |                 for(int i=0;i<s.size();i++)
      |                             ~^~~~~~~~~
foo.cc:20:27: warning: ‘a2’ may be used uninitialized [-Wmaybe-uninitialized]
   20 |                 cout<<a2<<" "<<a8<<" "<<a10<<" "<<a16<<endl;
      |                           ^~~
foo.cc:6:15: note: ‘a2’ was declared here
    6 |         int n,a2,a8,a10,a16;
      |               ^~
foo.cc:20:36: warning: ‘a8’ may be used uninitialized [-Wmaybe-uninitialized]
   20 |                 cout<<a2<<" "<<a8<<" "<<a10<<" "<<a16<<endl;
      |                                    ^~~
foo.cc:6:18: note: ‘a8’ was declared here
    6 |         int n,a2,a8,a10,a16;
      |                  ^~
foo.cc:20:46: warning: ‘a10’ may be used uninitialized [-Wmaybe-uninitialized]
   20 |                 cout<<a2<<" "<<a8<<" "<<a10<<" "<<a16<<endl;
      |                                              ^~~
foo.cc:6:21: note: ‘a10’ was declared here
    6 |         int n,a2,a8,a10,a16;
      |                     ^~~
foo.cc:20:51: warning: ‘a16’ may be used uninitialized [-Wmaybe-uninitialized]
   20 |                 cout<<a2<<" "<<a8<<" "<<a10<<" "<<a16<<endl;
      |                                                   ^~~
foo.cc:6:25: note: ‘a16’ was declared here
    6 |         int n,a2,a8,a10,a16;
      |                         ^~~