/in/foo.cc: In function 'int main()':
/in/foo.cc:20:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while (location < pre_path.size()) {
           ~~~~~~~~~^~~~~~~~~~~~~~~~~
/in/foo.cc:21:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (; location < pre_path.size() && pre_path[location] != '.'; location++) path.push_back(pre_path[location]);
            ~~~~~~~~~^~~~~~~~~~~~~~~~~
/in/foo.cc:22:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if (location + 1 < pre_path.size() && pre_path[location + 1] == '.'){
         ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
/in/foo.cc:26:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
      if (location < pre_path.size() && pre_path[location] == '/') location++;
          ~~~~~~~~~^~~~~~~~~~~~~~~~~
/in/foo.cc:29:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     else if(location<pre_path.size()) path.push_back(pre_path[location+1]);
             ~~~~~~~~^~~~~~~~~~~~~~~~