/in/foo.cc: In function 'int main()':
/in/foo.cc:7:22: warning: comparison with string literal results in unspecified behavior [-Waddress]
    7 |  while(cin>>n&&n[0]!="0"){
      |                      ^~~
/in/foo.cc:7:22: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
/in/foo.cc:10:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |   for(int i=0;i<n.length();i++){
      |               ~^~~~~~~~~~~