/in/foo.cc: In function 'int main()':
/in/foo.cc:13:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = 1; j < strlen(word); j++)
                   ~~^~~~~~~~~~~~~~
/in/foo.cc:33:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < strlen(doc); i++)
                  ~~^~~~~~~~~~~~~
/in/foo.cc:44:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int j = 1; j < strlen(word); j++)
                     ~~^~~~~~~~~~~~~~