/in/foo.cc: In function 'int main()':
/in/foo.cc:10:22: 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 i=0;i<=s.length();i++)  //判断完最后一个单词才能完成统计
      |                     ~^~~~~~~~~~~~
/in/foo.cc:12:34: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |                 if(s[i]==' ' || i==s.length())
      |                                 ~^~~~~~~~~~~~