foo.cc: In function 'int main()':
foo.cc:7:22: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
    7 |         if(s1.find(s)!=-1)cout<<s<<" is substring of "<<s1;
      |            ~~~~~~~~~~^~~~
foo.cc:8:27: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
    8 |         else if(s.find(s1)!=-1)cout<<s1<<" is substring of "<<s;
      |                 ~~~~~~~~~~^~~~

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