/in/foo.cc:15:25: error: stray '\342' in program
    num = 2 * num + s[i]-‘0’;
                         ^
/in/foo.cc:15:26: error: stray '\200' in program
    num = 2 * num + s[i]-‘0’;
                          ^
/in/foo.cc:15:27: error: stray '\230' in program
    num = 2 * num + s[i]-‘0’;
                           ^
/in/foo.cc:15:29: error: stray '\342' in program
    num = 2 * num + s[i]-‘0’;
                             ^
/in/foo.cc:15:30: error: stray '\200' in program
    num = 2 * num + s[i]-‘0’;
                              ^
/in/foo.cc:15:31: error: stray '\231' in program
    num = 2 * num + s[i]-‘0’;
                               ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:12:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < s.size(); i++)
                  ~~^~~~~~~~~~