顺序队列

SeqQueue.h

#pragma once

#include<iostream>
#define MAXSIZE 20
using namespace std;

template<class DataType>
class SeqQueue
{
public:
	SeqQueue();                        //无参构造函数 
	SeqQueue(DataType arr[], int n);   //带参构造函数，用一个数组初始化队列
	~SeqQueue();                       //析构函数
	int GetLength();                   //获得队列的长度
	int GetRemainder();                //获得队尾还允许入队的空间
	DataType GetHead();                //获取队首元素的值
	DataType DelHead();                //队首元素出队，并返回出队元素
	bool IsEmpty();                    //判断队列为空
	bool IsFull();                     //判断队列是否为满
	void EnQueue(DataType x);    	   //入队,将元素x插入到队列中
	void MoveAhead();                  //当队首出队后，整个队列应当向前移动k位，否则一直插入队尾元素会导致假溢出
	void Print();                      //打印队列
	void Clear();                      //清空队列

private:
	DataType *queue = new DataType[MAXSIZE]; //初始化时数组头为队首
	int front;    //队头指针
	int rear;     //队尾指针
	int length;   //队列长度
	int remainder;//队尾还允许入队的空间
};

/*
队列是一种受限的线性表。它只允许在表的一端进行插入，另一端进行删除。
队列具有“先入先出”的特性，它的应用非常广泛，它主要应用在树的层次遍历、图的广度优先遍历、键盘的输入缓冲区、操作系统和事务管理等方面。

【定义】
队列（queue）是一种先进先出（First In First Out , FIFO）的线性表，它只允许在表的一端插入元素，另一端删除元素。
其中，允许插入的一端称为队尾（rear），允许删除的一端称为对头（front）。

*/

SeqQueue.cpp

#include"SeqQueue.h"

template<class DataType>
SeqQueue<DataType>::SeqQueue()
{
	this->front  = 0;
	this->rear   = 0;
	this->length = 0;
	this->remainder = MAXSIZE;
}

template<class DataType>
SeqQueue<DataType>::SeqQueue(DataType arr[], int n)
{
	if (n > MAXSIZE) {
		return;
	}
	this->front = 0; //队首元素的下标初始化为零
	int i = 0;
	for (; i < n; i++) {
		this->queue[i] = arr[i];
	}
	this->rear      = i - 1;//队尾元素的下标初始化为 i-1
	this->length    = n;
	this->remainder = MAXSIZE - n;
}

template<class DataType>
SeqQueue<DataType>::~SeqQueue()
{
}

template<class DataType>
int SeqQueue<DataType>::GetLength()
{
	return this->length;
}

template<class DataType>
int SeqQueue<DataType>::GetRemainder()
{//队尾还能允许入队的空间由两件事决定：this->front / 2 >= this->remainder 这个条件是否能成立:
 //...若不成立，即使数组前端有空间也不能移动，此时允许入队的空间为 this->remainder;
 //...若成立，此时允许入队的空间应为 this->remainder 再加上元素向前移动后留出的空间即 this->front.
	if (this->front < 1) {
		return this->remainder;
	}
	else if (this->front / 2 >= this->remainder) {
		return this->remainder + this->front;
	}
	else{
		return this->remainder;
	}
	
}

template<class DataType>
DataType SeqQueue<DataType>::GetHead()
{
	if (this->IsEmpty())
		return -1;
	return this->queue[this->front];
}

template<class DataType>
DataType SeqQueue<DataType>::DelHead()
{
	if (this->IsEmpty())
		return -1;
	DataType temp = this->queue[this->front];
	this->front++;
	this->length--;
	return temp;
}

template<class DataType>
bool SeqQueue<DataType>::IsEmpty()
{
	if (this->length == 0)
		return true;
	else return false;
}

template<class DataType>
bool SeqQueue<DataType>::IsFull()
{
	if (this->length == MAXSIZE)
		return true;
	else return false;
}

template<class DataType>
void SeqQueue<DataType>::EnQueue(DataType x)
{
	if (this->IsFull())
		return;
	this->MoveAhead();
	this->queue[this->rear + 1] = x;
	this->rear++;
	this->length++;
	this->remainder--;
}

template<class DataType>
void SeqQueue<DataType>::MoveAhead()
{//当 this->remainder 充足时不使用此函数，因为移动元素将耗费时间为 o（this->length）
	if (this->front < 1)
		return;
	int k = this->front;
	if (k/2 >= this->remainder) { //当队首前的剩余空间/2 >= 队尾还允许入队的空间 时
		for (int i = 0; i < this->length; i++) {
			this->queue[i] = this->queue[i + k];
		}
		this->front = 0;
		this->rear -= k;
		this->remainder += k;
	}
}

template<class DataType>
void SeqQueue<DataType>::Print()
{
	if (this->IsEmpty())
		return;
	for (int i = this->front; i <= this->rear; i++) {
		cout << this->queue[i] << " ";
		if ((i-this->front+1) % 40 == 0)
			cout << endl;
	}
	cout << endl;
}

template<class DataType>
void SeqQueue<DataType>::Clear()
{
	this->front = 0;
	this->rear = 0;
	this->length = 0;
	this->remainder = MAXSIZE;
}

SeqQueueTest.cpp

#include<iostream>
#include"SeqQueue.cpp"
using namespace std;

int main()
{
	int arr[] = { 1,2,3,9,-4,15,-9,8,7,4,8,6,2,1,3,7,9,-11,10 };
	int nA    = sizeof(arr) / sizeof(arr[0]);

	SeqQueue<int> TestA(arr, nA);
	cout << "              打印队列：";
	TestA.Print();
	cout << "        获得队列的长度：" << TestA.GetLength() << endl;
	cout << "  队尾还允许入队的空间：" << TestA.GetRemainder() << endl;
	cout << "      获取队首元素的值：" << TestA.GetHead() << endl;
	cout << "          队首元素出队：" << TestA.DelHead() << endl;

	cout << "              打印队列：";
	TestA.Print();
	cout << "        获得队列的长度：" << TestA.GetLength() << endl;
	cout << "  队尾还允许入队的空间：" << TestA.GetRemainder() << endl;
	cout << "      获取队首元素的值：" << TestA.GetHead() << endl;
	cout << "  将元素33插入到队列中：" << endl;
	TestA.EnQueue(33);

	cout << "              打印队列：";
	TestA.Print();
	cout << "        获得队列的长度：" << TestA.GetLength() << endl;
	cout << "  队尾还允许入队的空间：" << TestA.GetRemainder() << endl;
	cout << "      获取队首元素的值：" << TestA.GetHead() << endl;

	cout << "  将元素34插入到队列中：" << endl;
	TestA.EnQueue(34);

	cout << "              打印队列：";
	TestA.Print();
	cout << "        获得队列的长度：" << TestA.GetLength() << endl;
	cout << "  队尾还允许入队的空间：" << TestA.GetRemainder() << endl;
	cout << "      获取队首元素的值：" << TestA.GetHead() << endl;

	cout << "      判断队列是否为满：" << TestA.IsFull() << endl;
	cout << "  队尾还允许入队的空间：" << TestA.GetRemainder() << endl;

	cout << "          队首元素出队：" << TestA.DelHead() << endl;
	cout << "          队首元素出队：" << TestA.DelHead() << endl;
	cout << "          队首元素出队：" << TestA.DelHead() << endl;
	cout << "          队首元素出队：" << TestA.DelHead() << endl;
	cout << "          队首元素出队：" << TestA.DelHead() << endl;
	cout << "          队首元素出队：" << TestA.DelHead() << endl;
	cout << "          队首元素出队：" << TestA.DelHead() << endl;

	cout << "              打印队列：";
	TestA.Print();
	cout << "        获得队列的长度：" << TestA.GetLength() << endl;
	cout << "  队尾还允许入队的空间：" << TestA.GetRemainder() << endl;
	cout << "      获取队首元素的值：" << TestA.GetHead() << endl;

	cout << "  将元素35插入到队列中：" << endl;
	TestA.EnQueue(35);

	cout << "              打印队列：";
	TestA.Print();
	cout << "        获得队列的长度：" << TestA.GetLength() << endl;
	cout << "  队尾还允许入队的空间：" << TestA.GetRemainder() << endl;
	cout << "      获取队首元素的值：" << TestA.GetHead() << endl;
	cout << "          判断队列为空：" << TestA.IsEmpty() << endl;
	cout << "              清空队列：" << endl;
	TestA.Clear();
	cout << "          判断队列为空：" << TestA.IsEmpty() << endl;

	return 0;
}