队列的基本操作实现

1. 链队列含头结点模型示意图如下：

2. 链队列结构定义如下：

// 结点类型
struct QueueNode {
    int data;
    QueueNode* next;
};

// 链队列结构
struct LinkQueue{
    QueueNode* front;
    QueueNode* rear;
};

3. 链队列的基本操作函数如下：

• LinkQueue* createLinkQueue(); // 创建队列头结点
• Insert(LinkQueue* head, int item); // 插入
• Delete(LinkQueue* head); // 出队，并返回数据

4. 具体代码实现如下：

#include <iostream>

using namespace std;

// 结点类型
struct QueueNode {
    int data;
    QueueNode* next;
};

// 链队列结构
struct LinkQueue{
    QueueNode* front;
    QueueNode* rear;
};

// 创建队列头结点
LinkQueue* createLinkQueue() {
    LinkQueue* head = (LinkQueue*)malloc(sizeof(LinkQueue));
    head->front = (QueueNode*)malloc(sizeof(QueueNode));
    head->front->data = 0;
    head->front->next = NULL;
    head->rear = head->front;
    return head;
}

// 插入
void Insert(LinkQueue* head, int item) {
    if (head == NULL) {
        head = createLinkQueue();
    }
    QueueNode* qnode = (QueueNode*)malloc(sizeof(QueueNode));
    qnode->data = item;
    qnode->next = NULL;
    head->rear->next = qnode;
    head->rear = qnode;
}

// 删除
int Delete(LinkQueue* head) {
    if (head == NULL || head->front == head->rear) {
        cout << "The linkqueue is empty." << endl;
        return 0;
    }
    QueueNode* temp = head->front->next;
    int val = temp->data;
    head->front->next = temp->next;
    if (temp == head->rear) {
        head->rear = head->front;
    }
    free(temp);
    return val;
}

int main() {
    LinkQueue* head = NULL;
    head = createLinkQueue();
    Insert(head, 1);
    Insert(head, 2);
    Insert(head, 3);
    Insert(head, 4);
    cout << Delete(head) << endl;
    cout << Delete(head) << endl;
    cout << Delete(head) << endl;
    cout << Delete(head) << endl;
    cout << Delete(head) << endl;
    system("pause");
    return 0;
}

5. 运行结果截图如下：