foo.cc: In function 'int main()':
foo.cc:17:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |  for (i = 0; i < s.length(); i++)
      |              ~~^~~~~~~~~~~~
foo.cc:48:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |  if (i == s.length() && flag == 0)
      |      ~~^~~~~~~~~~~~~

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