foo.cc: In function ‘void Dx()’:
foo.cc:6:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
    6 |         for(int j=0;j<t.size();j++)
      |                     ~^~~~~~~~~
foo.cc: In function ‘int main()’:
foo.cc:26:30: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   26 |                 for(int k=0;k<c.size();k++)
      |                             ~^~~~~~~~~