/in/foo.cc: In function 'int main()':
/in/foo.cc:9:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < strlen(b); ++i) if (a == b[i]) sum++;
                     ^
/in/foo.cc:10:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if (2*sum >= strlen(b)) cout << "Yes" << endl;
             ^