foo.cc: In function 'void check(std::__cxx11::string&)':
foo.cc:40:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(i=0;i<record.size();i++){
                 ~^~~~~~~~~~~~~~
foo.cc:45:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j=i;j<record.size();j++){
                     ~^~~~~~~~~~~~~~

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