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 < s1.size(); i++)
      |                 ~~^~~~~~~~~~~
foo.cc:12:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |  for(int i = 0; i < s2.size(); i++)
      |                 ~~^~~~~~~~~~~

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