foo.cc: In function 'void Test()':
foo.cc:31:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   31 |  for (int i = 0; i < c.size(); i++)
      |                  ~~^~~~~~~~~~
foo.cc:19:6: warning: unused variable 'k' [-Wunused-variable]
   19 |  int k = 0;
      |      ^

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