/in/foo.cc: In member function 'void UseVector::sort()':
/in/foo.cc:45:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<data.size()-1;i++)
               ~^~~~~~~~~~~~~~
/in/foo.cc:46:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int j = i+1; j < data.size(); j++)
                      ~~^~~~~~~~~~~~~
/in/foo.cc: In member function 'void UseVector::print()':
/in/foo.cc:59:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < data.size(); i++)
                   ~~^~~~~~~~~~~~~