顺序队列c++

通过数组建立队列

#include <iostream>

using namespace std;

template<class T>
class MyQueue
{
public:
    MyQueue(int queuecapacity=10);
    ~MyQueue();

    bool IsEmpty() const;
    T& Front() const;
    T& Rear() const;
    void Push(const T& item);
    void Pop();
private:
    T *Queue;
    int myfront;
    int myrear;
    int capacity;
};
template<class T>
inline MyQueue<T>::MyQueue(int queuecapacity):capacity(queuecapacity)
{
    if(capacity<1) throw "capacity must be > 0";
    Queue = new T[capacity];
    myfront = myrear = 0;
}

template<class T>
MyQueue<T>::~MyQueue()
{
    delete[] Queue;
}

template<class T>
bool MyQueue<T>::IsEmpty() const
{
    return myfront==myrear;
}

template<class T>
T& MyQueue<T>::Front() const
{
    if(IsEmpty()) throw "Queue is empty";
    return Queue[(myfront+1) % capacity];
}

template<class T>
T& MyQueue<T>::Rear() const
{
    if(IsEmpty()) throw "Queue is empty";
    return Queue[myrear];
}

template<class T>
void MyQueue<T>::Push(const T& item)
{
    if((myrear+1)%capacity==myfront)
    {
        T* newQueue = new T[2*capacity];
        int start = (myfront+1)%capacity;
        if(start<2)
        {
            copy(Queue+start,Queue+start+capacity-1,newQueue);
        }
        else
        {
            copy(Queue+start,Queue+capacity,newQueue);
            copy(Queue,Queue+myrear+1,newQueue+capacity-start);
        }
        myfront = 2*capacity-1;
        myrear = capacity-2;
        capacity *= 2;
        delete[] Queue;
        Queue = newQueue;
    }
    myrear = (myrear+1) % capacity;
    Queue[myrear] = item;
}

template<class T>
void MyQueue<T>::Pop()
{
    if(IsEmpty()) throw "Queue is empty";
    myfront = (myfront+1) % capacity;
    Queue[myfront].~T(); // 某课程上说这样写很厉害
}

int main()
{
    MyQueue<char> a(10);
    a.Push('A');
    a.Push('B');
    a.Push('C');
    a.Push('D');
    cout << a.Front() << endl;
    cout << a.Rear() << endl;
    a.Pop();
    a.Pop();
    cout << a.Front() << endl;
    cout << "Hello world!" << endl;
    return 0;
}