栈与队列实现

围绕两点，加深对栈与队列的理解

1 如何用两个栈实现一个队列

2 如何用两个队列实现一个栈

栈与队列 C++ 简易实现

typedef int DataType;
//简易栈
class stack
{
private:
    enum {size=10};
    DataType element[size];
    int top; //指向栈顶
public:
    stack():top(0) {}
    bool empty() { return top == 0; }
    bool full() { return top == size; }
    bool push (const DataType data);
    const DataType & pop();
};
bool stack::push (const DataType data)
{
    if (full())
    {
        return false;
    }
    element[top++] = data;
    return true;
}
const DataType & stack::pop()
{
    if (empty())
    {
        return -1;
    }
    return    element[--top];    
}
//简易队列
class Queue
{
private:
    struct Node
    {
        DataType data;
        Node * next;
    };
    Node * front; //队头
    Node * rear;  //队尾
    int length;
    const int qsize;
    Queue(const Queue & q):qsize(0) {}  //防止滥用拷贝，与赋值
    Queue & operator=(const Queue & q) { return *this; }
public:
    Queue(int qs);
    ~Queue();
    bool empty()const        { return front == rear;}
    bool full()const        { return length == qsize;}
    int getlength()const    { return length;}
    bool enqueue(const DataType &data);
    bool dequeue();
};
Queue::Queue(int qs):qsize(qs),length(0)
{
    front = new Node;
    front->next = NULL;
    rear = front;
}
Queue::~Queue()
{
    for (Node *p = front; p != NULL; )
    {
        Node *pTemp = p->next;
        delete p;
        p = pTemp;
    }
    front = rear = NULL;
}
bool Queue::enqueue(const DataType &data)
{
    if (full())
    {
        return false;
    }
    Node *p = new Node;
    p->data = data;
    p->next = NULL;
    rear->next = p;
    rear = p;
    ++length;
    return true;
}
bool Queue::dequeue()
{
    if (empty())
    {
        return false;
    }
    Node *p = front->next->next;
    delete front->next;
    front->next = p;
    if (p == NULL)
    {
        rear = front;
    }
    --length;
    return true;
}