foo.cc: In function 'int main()':
foo.cc:8:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    8 |  for(int i = 0; i < s.size(); i++) {
      |                 ~~^~~~~~~~~~
foo.cc:11:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |   for(int j = 0; j < s2.size(); j++)
      |                  ~~^~~~~~~~~~~

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