/in/foo.cc: In function 'int main()':
/in/foo.cc:70:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<s.length();i++){
              ~^~~~~~~~~~~
/in/foo.cc:84:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<left.size();i++){
              ~^~~~~~~~~~~~
/in/foo.cc:91:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<right.size();i++){
              ~^~~~~~~~~~~~~
/in/foo.cc:68:7: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
  char c;
       ^