两种队列

    typedef int Position;
    struct QNode {
        ElementType *Data;     /* 存储元素的数组 */
        Position Front, Rear;  /* 队列的头、尾指针 */
        int MaxSize;           /* 队列最大容量 */
    };
    typedef struct QNode *Queue;
     
    Queue CreateQueue( int MaxSize )
    {
        Queue Q = (Queue)malloc(sizeof(struct QNode));
        Q->Data = (ElementType *)malloc(MaxSize * sizeof(ElementType));
        Q->Front = Q->Rear = 0;
        Q->MaxSize = MaxSize;
        return Q;
    }
     
    bool IsFull( Queue Q )
    {
        return ((Q->Rear+1)%Q->MaxSize == Q->Front);
    }
     
    bool AddQ( Queue Q, ElementType X )
    {
        if ( IsFull(Q) ) {
            printf("队列满");
            return false;
        }
        else {
            Q->Rear = (Q->Rear+1)%Q->MaxSize;
            Q->Data[Q->Rear] = X;
            return true;
        }
    }
     
    bool IsEmpty( Queue Q )
    {
        return (Q->Front == Q->Rear);
    }
     
    ElementType DeleteQ( Queue Q )
    {
        if ( IsEmpty(Q) ) { 
            printf("队列空");
            return ERROR;
        }
        else  {
            Q->Front =(Q->Front+1)%Q->MaxSize;
            return  Q->Data[Q->Front];
        }
    }

    typedef struct Node *PtrToNode;
    struct Node { /* 队列中的结点 */
        ElementType Data;
        PtrToNode Next;
    };
    typedef PtrToNode Position;
     
    struct QNode {
        Position Front, Rear;  /* 队列的头、尾指针 */
        int MaxSize;           /* 队列最大容量 */
    };
    typedef struct QNode *Queue;
     
    bool IsEmpty( Queue Q )
    {
        return ( Q->Front == NULL);
    }
     
    ElementType DeleteQ( Queue Q )
    {
        Position FrontCell; 
        ElementType FrontElem;
         
        if  ( IsEmpty(Q) ) {
            printf("队列空");
            return ERROR;
        }
        else {
            FrontCell = Q->Front;
            if ( Q->Front == Q->Rear ) /* 若队列只有一个元素 */
                Q->Front = Q->Rear = NULL; /* 删除后队列置为空 */
            else                     
                Q->Front = Q->Front->Next;
            FrontElem = FrontCell->Data;
     
            free( FrontCell );  /* 释放被删除结点空间  */
            return  FrontElem;
        }
    }

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