/in/foo.cc: In function 'int main()':
/in/foo.cc:8:38: 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()-3;i++)
      |                                     ~^~~~~~~~~~~~~
/in/foo.cc:13:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |                         for(int i=0;i<=s1.size()-3;i++)
      |                                     ~^~~~~~~~~~~~~
/in/foo.cc:18:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   18 |                         for(int i=0;i<=s1.size()-4;i++)
      |                                     ~^~~~~~~~~~~~~
/in/foo.cc:23:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |                         for(int i=0;i<=s1.size()-1;i++)
      |                                     ~^~~~~~~~~~~~~