foo.cc: In function 'int main(int, char**)':
foo.cc:48:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |         for (i = 0; i < vtSet_C.size(); i++)
      |                     ~~^~~~~~~~~~~~~~~~
foo.cc: In function 'void DifferenceSet(std::vector<int>, std::vector<int>, std::vector<int>*)':
foo.cc:56:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |         for (i = 0; i < vtSet_A.size(); i++)
      |                     ~~^~~~~~~~~~~~~~~~
foo.cc:59:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |                 for (j = 0; j < vtSet_B.size(); j++)
      |                             ~~^~~~~~~~~~~~~~~~
foo.cc:55:49: warning: unused variable 'nIndex' [-Wunused-variable]
   55 |         int i, j, nSelectElement = 0, nTag = 0, nIndex = 0;
      |                                                 ^~~~~~

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