QElemType一直报错

#ifndef _LINKQUEUE_H_
#define _LINKQUEUE_H_
struct LinkNode{
  QElemType data;
  LinkNode* next;
};
struct LinkQueue
{
    LinkNode* front;
    LinkNode* rear; 
};
void InitQueue(LinkQueue&Q)
{
    Q.front = Q.rear = new LinkNode;
    Q.front->next = NULL;
}
void ClearQueue(LinkQueue&Q)
{
    LinkNode*p;
    while (Q.front->next != NULL)
    {
        p = Q.front->next;
        Q.front->next = p->next;
        delete p;
    }
    Q.rear = Q.front;
}
void DestroyQueue(LinkQueue& Q)
{
    ClearQueue(Q);
    delete Q.front;
    Q.front = Q.rear = NULL;
}
bool QueueEmpty(LinkQueue Q)
{
    return Q.front == Q.rear;
}
int QueueLength(LinkQueue Q)
{
    int i = 0;
    LinkNode* p = Q.front->next;
    while (p != NULL)
    {
        i++;
        p = p->next;
    }
    return i;
}
QElemType GetHead(LinkQueue& Q)
{
    return Q.front->next->data;
}
QElemType GetLast(LinkQueue& Q)
{
    return Q.rear->data;
}
void EnQueue(LinkQueue& Q, QElemType e)
{
    LinkNode* p;
    p = new LinkNode;
    p->data = e;
    p->next = NULL;
    Q.rear->next = p;
    Q.rear = p;
}
bool DeQueue(LinkQueue& Q, QElemType& e)
{
    if (QueueEmpty(Q))
        return false;
    LinkNode* p = Q.front->next;
    Q.front->next = p->next;
    e = p->data;
    if (p == Q.rear)
        Q.rear = Q.front;
    delete p;
    return true;
}

#endif // !_LINKQUEUE_H_