将图形类的获取周长和获取面积函数设置成虚函数，完成多态

#include <iostream>
#include <cmath>
#define PI 3.14159
using namespace std;

// 父类：图形类
class Shape
{
protected:
    double perimeter;
    double area;
public:
    Shape():perimeter(0),area(0) {}
    Shape(double p,double a):perimeter(p),area(a) {}
    virtual ~Shape() {}

    // 拷贝构造函数
    Shape(const Shape& other):perimeter(other.perimeter),area(other.area) {}

    // 拷贝赋值运算符
    Shape& operator=(const Shape& other)
    {
        if(this!=&other)
        {
            perimeter=other.perimeter;
            area=other.area;
        }
        return *this;
    }

    virtual double getPerimeter() const {return perimeter;}
    virtual double getArea() const {return area;}
};

// 子类：矩形类
class Rectangle:public Shape
{
private:
    double width;
    double height;
public:
    Rectangle(double w,double h):width(w),height(h)
    {
        perimeter=2*(width+height);
        area=width*height;
    }
    ~Rectangle() {}

    // 拷贝构造函数
    Rectangle(const Rectangle& other):Shape(other),width(other.width),height(other.height) {}

    // 拷贝赋值运算符
    Rectangle& operator=(const Rectangle& other)
    {
        if(this!=&other)
        {
            Shape::operator=(other);
            width=other.width;
            height=other.height;
        }
        return *this;
    }

    double getWidth() const {return width;}
    double getHeight() const {return height;}
};

// 子类：圆类
class Circle:public Shape
{
private:
    double radius;
public:
    Circle(double r):radius(r)
    {
        perimeter=2 * PI * radius;
        area=PI * radius * radius;
    }
    ~Circle() {}

    // 拷贝构造函数
    Circle(const Circle& other):Shape(other),radius(other.radius) {}

    // 拷贝赋值运算符
    Circle& operator=(const Circle& other)
    {
        if(this!=&other)
        {
            Shape::operator=(other);
            radius=other.radius;
        }
        return *this;
    }

    double getRadius() const { return radius; }
};

// 全局函数：打印图形信息
void printf(const Shape& shape)
{
    cout<<"周长: "<<shape.getPerimeter()<<endl;
    cout<<"面积: "<<shape.getArea()<<endl;
}
int main()
{

    // 创建矩形对象并测试
    Rectangle rect(3.0, 4.0);
    cout<<"矩形:"<<endl;
    cout<<"宽: "<<rect.getWidth()<<endl;
    cout<<"高: "<<rect.getHeight()<<endl;
    printf(rect);

    // 创建圆对象并测试
    Circle circle(5.0);
    cout<<"圆:"<<endl;
    cout<<"半径: "<<circle.getRadius()<<endl;
    printf(circle);

    return 0;
}

运行结果：

手动完成一个循环顺序队列

#include <iostream>

using namespace std;

class Queue
{
private:
    int* data;//存储队列元素的数组
    int capacity;//队列的容量
    int head;//指向队列头部的索引
    int tail;//指向队列尾部的索引
    int count;//当前队列中的元素数量

public:
    //构造函数，初始化队列
    Queue(int cap):capacity(cap),head(0),tail(0),count(0)
    {
        data=new int[capacity];
    }

    //析构函数，释放动态分配的内存
    ~Queue()
    {
        delete[] data;
    }

    //拷贝赋值运算符，实现深拷贝
    Queue& operator=(const Queue& other)
    {
        if(this!=&other)
        {
            delete[] data;
            capacity=other.capacity;
            head=other.head;
            tail=other.tail;
            count=other.count;
            data=new int[capacity];
            for(int i=0;i<capacity;++i)
            {
                data[i]=other.data[i];
            }
        }
        return *this;
    }

    // 访问第一个元素
    int front()
    {
        if(empty())
        {
            cerr<<"队列为空"<<endl;
            exit(EXIT_FAILURE);
        }
        return data[head];
    }

    // 访问最后一个元素
    int back()
    {
        if(empty())
        {
            cerr<<"队列为空"<<endl;
            exit(EXIT_FAILURE);
        }
        return data[(tail-1+capacity)%capacity];
    }

    // 判空
    bool empty() const
    {
        return count==0;
    }

    // 返回容纳的元素数
    int size() const
    {
        return count;
    }

    // 尾插元素
    void push(int value)
    {
        if (count==capacity)
        {
            cerr<<"队列已满"<<endl;
            return;
        }
        data[tail]=value;
        tail=(tail+1)%capacity;
        ++count;
    }

    // 头删元素
    void pop()
    {
        if(empty())
        {
            cerr<<"队列为空"<<endl;
            return;
        }
        head=(head+1)%capacity;
        --count;
    }

    // 遍历队列并展示各个元素
    void traverse() const
    {
        if(empty())
        {
            cout<<"队列为空"<<endl;
            return;
        }
        cout<<"队列中的元素:";
        for(int i=0;i<count;++i)
        {
            cout<<data[(head+i)%capacity]<<" ";
        }
        cout<<endl;
    }
};

int main()
{
    Queue queue(5); // 创建一个容量为5的循环队列
    queue.push(1); // 插入元素1
    queue.push(2); // 插入元素2
    queue.push(3); // 插入元素3
    queue.push(4); // 插入元素4
    queue.push(5); // 插入元素5

    cout<<"队首元素:"<<queue.front()<<endl;
    cout<<"队尾元素:"<<queue.back()<<endl;
    cout<<"队列大小:"<<queue.size()<<endl;

    queue.traverse();//遍历

    queue.pop();//头删
    cout<<"删除队首元素后队首元素:"<<queue.front()<<endl;
    cout<<"删除队首元素后队列大小:"<<queue.size()<<endl;

    queue.traverse();//再次遍历

    return 0;
}

运行结果：

今天课堂代码实现一遍：

思维导图：