foo.cc: In function 'int main()':
foo.cc:11:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < mystr.size(); i++)
                  ~~^~~~~~~~~~~~~~
foo.cc:20:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = locate; i < mystr.size(); i++)
                       ~~^~~~~~~~~~~~~~
foo.cc:20:25: warning: 'locate' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for (int i = locate; i < mystr.size(); i++)
                       ~~^~~~~~~~~~~~~~

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