/in/foo.cc: In function 'int main()':
/in/foo.cc:13:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < s2.size(); i++)
                  ~~^~~~~~~~~~~
/in/foo.cc:16:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = s1.size() - count; i < s1.size(); i++)
                                  ~~^~~~~~~~~~~