foo.cc: In member function 'void gjd::Add(std::vector<int>&)':
foo.cc:26:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while(i<v.size()&&i<v2.size())
               ~^~~~~~~~~
foo.cc:26:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while(i<v.size()&&i<v2.size())
                           ~^~~~~~~~~~
foo.cc:33:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while(i<v.size())
               ~^~~~~~~~~
foo.cc:40:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while(i<v2.size())
               ~^~~~~~~~~~

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