队列类(C++)

GeekLiHua

发布于 2025-01-21 14:25:51

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文章被收录于专栏：JavaJava

用C++实现队列

请设计通用队列类。

首先定义数据元素类型

typedef double ELEMENT; 然后定义队列

class QUEUE
{
public:
    QUEUE();
    ~QUEUE();
    bool Enqueue(const ELEMENT &value);
    bool Dequeue(ELEMENT &value);
    bool Clear();
    bool Empty() const;
    int Length() const;

    const static int queueSize;

private:
    int size, front, rear;
    ELEMENT *element;
};

const int QUEUE::queueSize = 5;

说明：

size 为动态数组的尺寸，front 为队首元素的下标，rear 为队尾元素下一位置的下标，element 为动态数组的起始地址。 queueSize 为动态数组的尺寸，初始值为 5。构造函数：初始化队列：将初始尺寸保存到 size，将队首 front 和队尾 rear 均置为 0，为动态数组分配内存并将起始地址保存到 element。析构函数：清理队列：释放动态数组的内存。 Enqueue 函数：若队列未满，则将元素 value 保存到队列中，函数值为 true；否则报告上溢错误，函数值为 false。 Dequeue 函数：若队列不空，则从队列中取出元素并保存到 value中，函数值为 true；否则报告下溢错误，函数值为 false。 Clear 函数：清空队列，将 front 和 rear 重置为 0，操作成功，函数值为 true。 Empty 函数：若队列空，则函数值为 true，否则为 false。 Length 函数：函数值为队列中元素的数量。提示：循环队列最多装 queueSize - 1 个元素。

裁判程序

#include <iostream>
#include <iomanip>
using namespace std;
#include <cctype>

typedef double ELEMENT;

class QUEUE
{
public:
    QUEUE();
    ~QUEUE();
    bool Enqueue(const ELEMENT &value);
    bool Dequeue(ELEMENT &value);
    bool Clear();
    bool Empty() const;
    int Length() const;

    const static int queueSize;

private:
    int size, front, rear;
    ELEMENT *element;
};

const int QUEUE::queueSize = 5;

/* 你提交的代码将被嵌在这里 */

int main()
{
    QUEUE queue;
    ELEMENT value;
    char choice;
    do
    {
        cout << "eNqueue Dequeue Clear Empty Length Quit > ";
        cin >> choice;
        choice = toupper(choice);
        
        switch (choice)
        {
        case 'N':
            cout << "Value: ";
            cin >> value;
            if (queue.Enqueue(value))
            {
                cout << "Enqueue successfully!\n";
            }
            else
            {
                cout << "Enqueue failed!\n";
            }
            break;
        case 'D':
            if (queue.Dequeue(value))
            {
                cout << "Dequeue successfully!\n";
                cout << "Value: " << value << endl;
            }
            else
            {
                cout << "Dequeue failed!\n";
            }
            break;
        case 'C':
            if (queue.Clear())
            {
                cout << "Clear successfully!\n";
            }
            else
            {
                cout << "Clear failed!\n";
            }
            break;
        case 'E':
            if (queue.Empty())
            {
                cout << "Queue is empty!\n";
            }
            else
            {
                cout << "Queue is not empty!\n";
            }
            break;
        case 'L':
            cout << "Queue length: " << queue.Length() << endl;
            break;
        case 'Q':
            break;
        default:
            cout << "Incorrect choice!\n";
        }
    }
    while (choice != 'Q');
}

测试样例1

eNqueue Dequeue Clear Empty Length Quit > t
Incorrect choice!
eNqueue Dequeue Clear Empty Length Quit > K
Incorrect choice!
eNqueue Dequeue Clear Empty Length Quit > Q

测试样例2

eNqueue Dequeue Clear Empty Length Quit > L
Queue length: 0
eNqueue Dequeue Clear Empty Length Quit > e
Queue is empty!
eNqueue Dequeue Clear Empty Length Quit > N
Value: 4.5
Enqueue successfully!
eNqueue Dequeue Clear Empty Length Quit > n
Value: 1.6
Enqueue successfully!
eNqueue Dequeue Clear Empty Length Quit > l
Queue length: 2
eNqueue Dequeue Clear Empty Length Quit > E
Queue is not empty!
eNqueue Dequeue Clear Empty Length Quit > d
Dequeue successfully!
Value: 4.5
eNqueue Dequeue Clear Empty Length Quit > D
Dequeue successfully!
Value: 1.6
eNqueue Dequeue Clear Empty Length Quit > D
Queue underflow!
Dequeue failed!
eNqueue Dequeue Clear Empty Length Quit > q

测试样例3

eNqueue Dequeue Clear Empty Length Quit > n
Value: 1.7
Enqueue successfully!
eNqueue Dequeue Clear Empty Length Quit > n
Value: 2.8
Enqueue successfully!
eNqueue Dequeue Clear Empty Length Quit > n
Value: 3.6
Enqueue successfully!
eNqueue Dequeue Clear Empty Length Quit > n
Value: 4.9
Enqueue successfully!
eNqueue Dequeue Clear Empty Length Quit > n
Value: 9.9
Queue overflow!
Enqueue failed!
eNqueue Dequeue Clear Empty Length Quit > L
Queue length: 4
eNqueue Dequeue Clear Empty Length Quit > e
Queue is not empty!
eNqueue Dequeue Clear Empty Length Quit > C
Clear successfully!
eNqueue Dequeue Clear Empty Length Quit > l
Queue length: 0
eNqueue Dequeue Clear Empty Length Quit > E
Queue is empty!
eNqueue Dequeue Clear Empty Length Quit > n
Value: 8.5
Enqueue successfully!
eNqueue Dequeue Clear Empty Length Quit > D
Dequeue successfully!
Value: 8.5
eNqueue Dequeue Clear Empty Length Quit > q

输出样例

eNqueue Dequeue Clear Empty Length Quit >

输入样例 q

提交代码：

QUEUE::QUEUE()
{
    this->front = this->rear = 0;
    this->size = queueSize;
    element = new ELEMENT[this->size];
}
QUEUE::~QUEUE()
{
    front = rear = 0;
    delete []element;
}
bool QUEUE::Enqueue(const ELEMENT &value)
{
    if ((this->rear + 1) % this->size == this->front || QUEUE::Length() >= this->size || this->rear >= this->size)
    {
        cout << "Queue overflow!\n";
        return false;
    }
    this->element[this->rear % this->size] = value;
    this->rear = (this->rear + 1) % this->size;
    return true;
}
bool QUEUE::Dequeue(ELEMENT &value)
{
    if (this->front % this->size == this->rear % this->size)
    {
        cout << "Queue underflow!\n";
        return false;
    }
    value = element[this->front % this->size];
    this->front = (this->front + 1) % this->size;
    return true;
}
bool QUEUE::Clear()
{
    this->front = this->rear = 0;
    return true;
}
bool QUEUE::Empty() const
{
    return this->rear == this->front;
}
int QUEUE::Length() const
{
    return (this->rear - this->front + this->size) % this->size;
}

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原始发表：2024-02-01，如有侵权请联系 cloudcommunity@tencent.com 删除

测试