foo.cc: In function 'int main()':
foo.cc:8:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    8 |  while(i<s.size()){
      |        ~^~~~~~~~~
foo.cc:10:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   10 |   for(int j=i,k=0;k<s1.size();k++,j++)
      |                   ~^~~~~~~~~~

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