/in/foo.cc: In function 'std::string to10(std::string)':
/in/foo.cc:7:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    7 |         for(int i=0;i<x.size();i++)
      |                     ~^~~~~~~~~
/in/foo.cc:12:22: 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<x.size();i++)
      |                     ~^~~~~~~~~
/in/foo.cc: In function 'std::string to16(std::string)':
/in/foo.cc:25:21: error: 'k' was not declared in this scope
   25 |                 jz*=k;
      |                     ^
/in/foo.cc:27:16: error: could not convert 'ans' from 'int' to 'std::string' {aka 'std::__cxx11::basic_string<char>'}
   27 |         return ans;
      |                ^~~
      |                |
      |                int