/in/foo.cc: In function 'void td(std::__cxx11::string, std::__cxx11::string)':
/in/foo.cc:7:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<t.length();k++)
          ~^~~~~~~~~~~
/in/foo.cc:7:23: error: 'k' was not declared in this scope
  for(i=0;i<t.length();k++)
                       ^
/in/foo.cc:22:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<t.length();k++)
          ~^~~~~~~~~~~
/in/foo.cc:22:23: error: 'k' was not declared in this scope
  for(i=0;i<t.length();k++)
                       ^