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.length(); i++)
      |                  ~^~~~~~~~~~~
foo.cc:10:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |         if(i==s.length()-1)
      |            ~^~~~~~~~~~~~~~

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