队列顺序实现

C++编译器

基本操作思想

循环队列(逻辑上，留一个空间为空)

定义存放元素的数组最大长度MAXSIZE。

定义表头指针front，表尾指针rear。且初始化表头表尾指针相等且为0。

判断是否队列是否为空:front==rear。

判断队列是否已满:front==(rear+1)%MAXSIZE。

获取队列长度:(rear-front+MAXSIZE)%MAXSIZE。

进队后队尾指针操作:rear = (rear+1)%MAXSIZE。

出队后队头指针操作:front = (front+1)%MAXSIZE。

源代码

#include <stdio.h>
#define MAXSIZE 10
#define INITQUEUESTATUS 0
#define NAN -999999

struct Queue {
	int data[MAXSIZE];
	int front;
	int rear;
	/*
	初始化队列
	*/
	void initQueue() {
		this->front = INITQUEUESTATUS;
		this->rear = INITQUEUESTATUS;
	}
	
	/*
	入队操作
	*/
	void enQueue(int value) {
		if (this->isFull()) {
			printf("this Queue is full,can not push\n");
			return;
		}
		this->data[this->rear] = value;
		this->rear = (this->rear + 1) % MAXSIZE;
	}
	/*
	出队操作
	*/
	int deQueue() {
		if (this->isEmpty()) {
			printf("this Queue is empty,can not pop\n");
			return NAN;
		}
		int value = this->data[this->front];
		this->front = (this->front + 1) % MAXSIZE;
		return value;
	}
	/*
	获取队头元素值
	*/
	int getHead() {
		if (this->isEmpty()) {
			printf("this Queue is empty,not have head element");
			return NAN;
		}
		return this->data[this->front];
	}
	
	/*
	获取队列长度
	*/
	int lenth() {
		return (this->rear - this->front + MAXSIZE) % MAXSIZE;
	}
	/*
	判断队列是否已满
	*/
	bool isFull() {
		return (this->rear + 1) % MAXSIZE == this->front;
	}
	
	/*
	判断队列是否为空
	*/
	bool isEmpty() {
		return this->front == this->rear;
	}

	void print() {
		if (this->isEmpty()) {
			printf("this Queue is empty\n");
			return;
		}
		int index = this->front;
		while (index != this->rear) {
			printf("%d ", this->data[index]);
			index = (index + 1) % MAXSIZE;
		}
		printf("lenth=%d\n", this->lenth());
	}
};

int main() {

	Queue queue;
	queue.initQueue();
	for (int i = 0; i < 10; i++) {
		queue.enQueue(i);
	}

	queue.print();

	for (int i = 0; i < 5; i++) {
		queue.deQueue();
	}

	queue.print();

	printf("this Queue head value=%d\n", queue.getHead());


	for (int i = 0; i < 6; i++) {
		queue.enQueue(i);
	}

	queue.print();

	printf("this Queue head value=%d\n", queue.getHead());

	for (int i = 0; i < 10; i--) {
		int value = queue.deQueue();
		if (value == NAN) {
			break;
		}
	}

	return 0;
}

运行截图