/in/foo.cc: In member function 'bool stu::operator<(const stu&) const':
/in/foo.cc:13:11: warning: statement has no effect [-Wunused-value]
          a>t.a;
           ^
/in/foo.cc:14:5: warning: no return statement in function returning non-void [-Wreturn-type]
     }
     ^