foo.cc: In function 'int Search(std::string&, char)':
foo.cc:7:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    7 |         for(int i=0;i<s.length();i++)
      |                     ~^~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:18:17: 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<s.length();i++)
      |                ~^~~~~~~~~~~

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