通过设置标志位tag判断队空队满的循环队列

Queue

bool

tag

tag

rear==front&&!tag

rear==front&&tag

#ifndef QUEUE_H
#define QUEUE_H

#include<iostream>
using namespace std;

template<class T>
class Queue {
private:
int maxSize;    //存放队列数组的大小
int front;      //表示队头所在位置的下标
int rear;       //表示队尾所在位置的下标
int *queue;     //存放类型为T的队列元素的数组
bool tag;       //0为空，1为不空
public:
Queue(int size);
~Queue() {
delete[] queue;
}
void Clear();       //清空队列
bool EnQueue(const T item);     //item入队，插入队尾
bool DeQueue(T & item);         //返回队头元素，并删除该元素
bool GetFront(T & item);        //返回队头元素但不删除
void disPlay();                 //输出队列
};
template<class T>
Queue<T>::Queue(int size) {
maxSize = size;
tag = 0;
queue = new T[maxSize];
front = rear = 0;
}
template<class T>
void Queue<T>::Clear() {
front = rear;
tag = 0;
}
template<class T>
bool Queue<T>::EnQueue(const T item) {
if (rear==front&&tag) {
cout << "队列已满，溢出！" << endl;
return false;
}
queue[rear] = item;
rear = (rear + 1) % maxSize;
tag = 1;//入队列设为1
return true;
}
template<class T>
bool Queue<T>::DeQueue(T & item) {
if (rear==front&&!tag) {
cout << "队列为空，溢出！" << endl;
return false;
}
item = queue[front];
front = (front + 1) % maxSize;
tag = 0;//出队列设为0
return true;
}
template<class T>
bool Queue<T>::GetFront(T & item) {
if (rear==front&&!tag) {
cout << "队列为空，溢出！" << endl;
return false;
}
item = queue[front];
return true;
}
template<class T>
void Queue<T>::disPlay() {
if (rear==front&&!tag) {
cout << "队列为空！" << endl;
return;
}
if (front == rear&&tag!=0) {
for (int i = 0; i < maxSize; i++) {
cout << queue[i] << " ";
}
}
for (int i = front;; i = (i + 1) % maxSize) {
if (i == rear)
break;
cout << queue[i] << " ";
}
cout << endl;
}
#endif // !QUEUE_H

#include<iostream>
#include"queue.h"
using namespace std;

int main() {
Queue<int> q(7);
int i = 0;
int item = 0;
q.EnQueue(0);
q.disPlay();
q.EnQueue(1);
q.disPlay();
q.EnQueue(2);
q.disPlay();
q.EnQueue(3);
q.disPlay();
q.EnQueue(4);
q.disPlay();
q.EnQueue(5);
q.disPlay();
q.EnQueue(6);
q.disPlay();
q.EnQueue(7);
q.disPlay();
q.DeQueue(item);
q.EnQueue(6);
q.disPlay();
for (int j = 0; j < 7; j++) {
q.DeQueue(item);
i++;
q.disPlay();
}
return 0;
}