c++ 实现队列

相关资料：

• 用C++实现一个队列
• 数据结构代码实现之队列的链表实现(C/C++)

// 1. 过程抽象与封装实现队列

#include <iostream>
using namespace std;

const int MAX_QUEUE_SIZE = 100; // 队列最大容量
// 数组实现的队列结构体
struct Queue
{
    int front; // 队首元素数组下标
    int rear; // 队尾元素数组下标
    int size; // 当前队列大小
    int buffer[MAX_QUEUE_SIZE];
};

// 队列初始化
void init(Queue &q)
{
    q.front = q.rear = 0;
    q.size = 0;
}

// 入队操作
void push(Queue &q, int i)
{
    if (q.size == MAX_QUEUE_SIZE)
    {
        cout << "Queue is overflow.\n";
        exit(-1);
    }
    else
    {
        q.buffer[q.rear] = i;
        q.rear = (q.rear + 1) % MAX_QUEUE_SIZE;
        q.size += 1;
        return;
    }
}

// 出队操作
void pop(Queue &q, int &i)
{
    if (q.size == 0)
    {
        cout << "Queue is empty.\n";
        exit(-1);
    }
    else
    {
        i = q.buffer[q.front];
        q.front = (q.front + 1) % MAX_QUEUE_SIZE;
        q.size -= 1;
        return;
    }
}

// 获取队首/队尾元素
void get_queue(Queue &q)
{
    if (q.front == q.rear)
    {
        cout << "Queue is empty.\n";
    }
    else
    {
        cout << "front element: " << q.buffer[q.front] << endl;
        cout << "rear element: " << q.buffer[q.rear-1] << endl;
        cout << "front index: " << q.front << endl;
        cout << "rear index: " << q.rear << endl;
        cout << "queue size: " << q.size << endl;
        return;
    }
}

int main()
{
    Queue q;
    int x;
    init(q);
    push(q, 2);
    push(q, 3);
    push(q, 4);
    pop(q, x);
    get_queue(q);

    return 0;
}

// 2. 数据抽象与封装实现队列
// 2.1 数组实现

#include <iostream>
using namespace std;
const int MAX_QUEUE_SIZE = 100;

class Queue
{
public:
    Queue();
    void push(int i);
    void pop(int &i);
    void get_queue();

private:
    int front; // 队首元素数组下标
    int rear; // 队尾元素数组下标
    int size; // 当前队列大小
    int buffer[MAX_QUEUE_SIZE];
};

// 队列初始化
Queue::Queue()
{
    front = rear = 0;
    size = 0;
}

// 入队操作
void Queue::push(int i)
{
    if (size == MAX_QUEUE_SIZE)
    {
        cout << "Queue is overflow.\n";
        exit(-1);
    }
    else
    {
        buffer[rear] = i;
        rear = (rear + 1) % MAX_QUEUE_SIZE;
        size += 1;
        return;
    }
}

// 出队操作
void Queue::pop(int &i)
{
    if (size == 0)
    {
        cout << "Queue is empty.\n";
        exit(-1);
    }
    else
    {
        i = buffer[front];
        front = (front + 1) % MAX_QUEUE_SIZE;
        size -= 1;
        return;
    }
}

// 获取队首/队尾元素
void Queue::get_queue()
{
    if (front == rear)
    {
        cout << "Queue is empty.\n";
    }
    else
    {
        cout << "front element: " << buffer[front] << endl;
        cout << "rear element: " << buffer[rear-1] << endl;
        cout << "front index: " << front << endl;
        cout << "rear index: " << rear << endl;
        cout << "queue size: " << size << endl;
        return;
    }
}

int main()
{
    Queue q;
    int x;
    q.push(12);
    q.push(15);
    q.push(20);
    q.pop(x);
    q.get_queue();

    return 0;
}