/in/foo.cc: In function 'int main()':
/in/foo.cc:16:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (size_t i = 0; i < count1; i++)
                     ~~^~~~~~~~
/in/foo.cc:18:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (size_t i = 0; i < count2; i++)
                     ~~^~~~~~~~
/in/foo.cc:24:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (size_t i = 0; i < count2; i++)
                     ~~^~~~~~~~
/in/foo.cc:29:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (size_t j = 0; j < count1; j++)
                      ~~^~~~~~~~
/in/foo.cc:34:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if (j == count1 - 1)
        ~~^~~~~~~~~~~~~
/in/foo.cc:47:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (size_t j = 0; j < count2; j++)
                      ~~^~~~~~~~