foo.cc: In function 'int main()':
foo.cc:12:14: 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(i=0;i<s.length()-s1.length()+1;i++)
      |             ~^~~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:15:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |         for(int j=0;j<s1.length();j++)
      |                     ~^~~~~~~~~~~~

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