foo.cc: In function 'int main()':
foo.cc:19:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |     for (int i = 0; i < arr.length(); i++)
      |                     ~~^~~~~~~~~~~~~~
foo.cc:33:13: warning: 'max_sp' may be used uninitialized [-Wmaybe-uninitialized]
   33 |     cout << max_sp << endl;
      |             ^~~~~~
foo.cc:15:10: note: 'max_sp' was declared here
   15 |     char max_sp;
      |          ^~~~~~

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