/in/foo.cc:8:1: warning: multi-line comment [-Wcomment]
 //          / \\|||   :   |||// \
 ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:34:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < v.size(); i++)
                  ~~^~~~~~~~~~