用数组实现队列（C++）

#include <iostream>

using namespace std;

template<typename T, int size = 0>
class Queue
{
public:
    Queue();

    bool isEmpty() const;
    bool isFull()const;

    void enQueue(const T&);
    T deQueue();

    void traverse()const;
private:
    T storge[size];
    int first;
    int last;
};

template<typename T, int size>
Queue<T, size>::Queue()
{
    first = last = -1;
}

template<typename T, int size>
bool Queue<T, size>::isEmpty()const
{
    //如果为空，first必然为-1,因为在deQueue()出栈函数中已经处理
    return first == -1;
}

template<typename T, int size>
bool Queue<T, size>::isFull()const
{
    //两种情况，第一种是正常的满，第二种是存在出队时的满
    return first == 0 && last == size - 1 || last == first - 1;
}


template<typename T, int size>
void Queue<T, size>::enQueue(const T& elem)
{
    if (!isFull())
    {
        //last为-1或指向最后一个元素的位置时
        if (last == -1 || last == size - 1)
        {
            storge[0] = elem;
            last = 0;
            //若队列为空，还需将first赋为0
            if (first == -1)
            {
                first = 0;
            }
        }
        else
        {
            storge[++last] = elem;
        }
    }
    else
    {
        cout << "Queue full." << endl;
        exit(1);
    }
}

template<typename T, int size>
T Queue<T, size>::deQueue()
{
    if (isEmpty())
    {
        cout << "Queue empty." << endl;
        exit(1);
    }
    T temp;
    temp = storge[first];
    //队列中只有一个元素时
    if (first == last)
    {
        //这样，判断是否为空时只需判定first是否为-1
        first = last = -1;
    }
    else if (first == size - 1)
    {
        //回到第一个元素位置
        first = 0;
    }
    else
    {
        ++first;
    }
    return temp;
}

template<typename T, int size>
void Queue<T, size>::traverse()const
{
    for (auto i = first; i <= last; ++i)
    {
        cout << storge[i] << " ";
    }
    cout << endl;
}


int main()
{
    Queue<int, 3> queue;

    queue.enQueue(10);
    queue.enQueue(10);
    queue.enQueue(10);

    cout << queue.isFull() << endl;

    queue.traverse();
    queue.deQueue();
    queue.traverse();
    queue.deQueue();
    cout << queue.isEmpty() << endl;
    queue.deQueue();
    cout << queue.isEmpty() << endl;
    system("pause");
    return 0;
}

运行测试：

参考：C++实现队列--数组实现和链表实现