/in/foo.cc:31:19: warning: multi-character character constant [-Wmultichar]
    if (line[j] == '/0')
                   ^~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:29:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int j = number; j < line.size(); j++)
                        ~~^~~~~~~~~~~~~