View Compilation Error

0_0_17159105_21221.cpp: In function 'int bfs(NODE)':
0_0_17159105_21221.cpp:28:12: error: cannot convert 'std::queue<_Tp, _Sequence>::empty<NODE, std::deque<NODE, std::allocator<NODE> > >' from type 'bool (std::queue<NODE>::)() const' to type 'bool'
  while (!q.empty) q.pop();
            ^
0_0_17159105_21221.cpp:28:12: error: in argument to unary !
0_0_17159105_21221.cpp:33:12: error: cannot convert 'std::queue<_Tp, _Sequence>::empty<NODE, std::deque<NODE, std::allocator<NODE> > >' from type 'bool (std::queue<NODE>::)() const' to type 'bool'
  while (!q.empty) {
            ^
0_0_17159105_21221.cpp:33:12: error: in argument to unary !