本文实例为大家分享了C++实现循环队列的具体代码，供大家参考，具体内容如下
circularQueue.h
#pragma once
#pragma once
#ifndef CIRCULARQUEUE_H
#define CIRCULARQUEUE_H
#include<iostream>
#include<ostream>
using std::cout;
using std::cin;
using std::endl;
using std::ostream;
template<class T> class cirQueue;
template<typename T>
class cirQueue
{
public:
cirQueue(int sz);
~cirQueue();
void push(const T& elem);//进队
void pop(T& elem);//出队
bool empty();//查看队列是否为空
int getSize();//返回队列中元素的个数
void clearQueue();//清空队列中的元素
void print();//打印队列中的元素
int getfront() { return front; }
int getrear() { return rear; }
bool getTop(T& elem);//读取队列首个元素
template<typename T>
friend ostream& operator<<(ostream& os, cirQueue<T>& queue);
private:
bool _full()const;//判断队列是否已满
int maxsize;//队列最大的空间
T* element;//存放于队列中的元素数组
int front;//模拟队头指针
int rear;//模拟队尾指针
};
template<typename T>
cirQueue<T>::cirQueue(int sz) {
maxsize = sz;
element = new T[maxsize];
if (element == nullptr)
cout << "内存分配失败" << endl;
front = 0;
rear = 0;
}
template<typename T>
cirQueue<T>::~cirQueue() {
if (element != nullptr)
delete element;
}
//进队
template<typename T>
void cirQueue<T>::push(const T& elem) {//需要保证队尾指针位置与首个元素相差一个位置
if (rear > (maxsize - 1))
rear -= maxsize ;
if (front > (maxsize - 1))
front -= maxsize ;
if (!_full()) {//队列未满的情况
element[rear++] = elem;//队尾向后移动一位
//++rear;
}
else {
cout << "队列已满，不能插入！" << endl;
return;
}
}
//出队
template<typename T>
void cirQueue<T>::pop(T& elem) {
if (rear > (maxsize - 1))
rear -= (maxsize - 1);
if (front > (maxsize - 1))
front -= (maxsize - 1);
if (!empty()) {//队列未空的情况
elem = element[front++];//队头向后移动一位
element[front - 1] = 0;//置零
}
else {
cout << "队列已空！" << endl;
return;
}
}
//查看队列是否为空
template<typename T>
bool cirQueue<T>::empty() {
if (front == rear)//待定
return true;
return false;
}
//返回队列中元素的个数
template<typename T>
int cirQueue<T>::getSize() {
int num = 0;
if (front <= rear)
return rear - front;
else
return maxsize - front + rear + 1;
}
//清空队列中的元素
template<typename T>
void cirQueue<T>::clearQueue() {
if (!empty())
{
int Index = 0;
while (front < rear) {//front逼近rear
element[front++] = 0;
if (front == rear)
return;
}
if (rear < front) {
while (front <= maxsize - 1)//删除front至数组尾端的数据
element[front++] = 0;
front -= maxsize;
while (front < rear) {//删除front至rear的数据
element[front++] = 0;
if (front == rear)
return;
}
}
}
}
//打印队列中的元素
template<typename T>
void cirQueue<T>::print() {//与clearQueue函数原理一致，将front替换为Index
if (!empty())
{
int Index = front;
while (Index < rear) {
cout << element[Index++] << " ";
if (Index == rear) {
cout << endl;
return;
}
}
if (rear < Index) {
while (Index <= maxsize - 1)
cout << element[Index++] << " ";
Index -= maxsize;
while (Index < rear) {
cout << element[Index++] << " ";
if (Index == rear) {
cout << endl;
return;
}
}
}
}
}
//读取队列首个元素
template<typename T>
bool cirQueue<T>::getTop(T& elem) {
if (!empty()) {
elem = element[front];
return true;
}
return false;
}
template<typename T>
ostream& operator<<(ostream& os, cirQueue<T>& queue) {
os << "队列中的元素数量为：" << queue.getSize() << endl;
return os;
}
//判断队列是否已满
template<typename T>
bool cirQueue<T>::_full()const {
if (front - rear == 1 || front - rear == -maxsize + 1)
return true;
return false;
}
#endif // !CIRCULARQUEUE_H
main.cpp
#include"CircularQueue.h"
int main()
{
cirQueue<int> cq(20);
int a = 0;
for (int i = 0; i < 19; i++)
{
cq.push(i);
}
cq.print();
cout << cq;
for (int i = 0; i < 20; i++)
{
cq.pop(a);
}
cout << cq;//此时front=rear=19
cout << cq.getfront() << " " << cq.getrear() << endl;
//for (int i = 19; i < 25; i++)
//{
// cq.push(i);
//}
cq.push(19);
cq.print();
cout << cq.getfront() << " " << cq.getrear() << endl;
cout << endl << endl;
cq.push(20);
cq.getTop(a);
cout << a << endl;
cq.print();
cout << cq.getfront() << " " << cq.getrear() << endl;
return 1;
}
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