foo.cc: In function 'int main()':
foo.cc:17:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |                 for (; j < num.size(); j++)
      |                        ~~^~~~~~~~~~~~
foo.cc:20:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |                 if(j >= num.size())
      |                    ~~^~~~~~~~~~~~~
foo.cc:26:26: 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 (; j < num.size(); j++)
      |                        ~~^~~~~~~~~~~~
foo.cc:29:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |                 if (j >= num.size())
      |                     ~~^~~~~~~~~~~~~

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