foo.cc: In function 'void getnext(std::string)':
foo.cc:11:10: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |  while (j<a.size() - 1)
      |         ~^~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:52:7: warning: unused variable 'm' [-Wunused-variable]
   52 |   int m = a.size();
      |       ^
foo.cc:54:7: warning: unused variable 'q' [-Wunused-variable]
   54 |   int q = c.size();
      |       ^

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