实验5

一

 

#pragma once

#include <string>

// 发行/出版物类：Publisher （抽象类）
class Publisher {
public:
    Publisher(const std::string& name_ = "");            // 构造函数
    virtual ~Publisher() = default;

public:
    virtual void publish() const = 0;                 // 纯虚函数，作为接口继承
    virtual void use() const = 0;                     // 纯虚函数，作为接口继承

protected:
    std::string name;    // 发行/出版物名称
};

// 图书类: Book
class Book : public Publisher {
public:
    Book(const std::string& name_ = "", const std::string& author_ = "");  // 构造函数

public:
    void publish() const override;        // 接口
    void use() const override;            // 接口

private:
    std::string author;          // 作者
};

// 电影类: Film
class Film : public Publisher {
public:
    Film(const std::string& name_ = "", const std::string& director_ = "");   // 构造函数

public:
    void publish() const override;    // 接口
    void use() const override;        // 接口            

private:
    std::string director;        // 导演
};


// 音乐类：Music
class Music : public Publisher {
public:
    Music(const std::string& name_ = "", const std::string& artist_ = "");

public:
    void publish() const override;        // 接口
    void use() const override;            // 接口

private:
    std::string artist;      // 音乐艺术家名称
};
#include <iostream>
#include <string>
#include "publisher.hpp"

// Publisher类：实现
Publisher::Publisher(const std::string& name_) : name{ name_ } {
}


// Book类: 实现
Book::Book(const std::string& name_, const std::string& author_) : Publisher{ name_ }, author{ author_ } {
}

void Book::publish() const {
    std::cout << "Publishing book《" << name << "》 by " << author << '\n';
}

void Book::use() const {
    std::cout << "Reading book 《" << name << "》 by " << author << '\n';
}


// Film类：实现
Film::Film(const std::string& name_, const std::string& director_) :Publisher{ name_ }, director{ director_ } {
}

void Film::publish() const {
    std::cout << "Publishing film <" << name << "> directed by " << director << '\n';
}

void Film::use() const {
    std::cout << "Watching film <" << name << "> directed by " << director << '\n';
}


// Music类：实现
Music::Music(const std::string& name_, const std::string& artist_) : Publisher{ name_ }, artist{ artist_ } {
}

void Music::publish() const {
    std::cout << "Publishing music <" << name << "> by " << artist << '\n';
}

void Music::use() const {
    std::cout << "Listening to music <" << name << "> by " << artist << '\n';
}
#include <memory>
#include <iostream>
#include <vector>
#include "publisher.hpp"

void test1() {
    std::vector<Publisher*> v;

    v.push_back(new Book("Harry Potter", "J.K. Rowling"));
    v.push_back(new Film("The Godfather", "Francis Ford Coppola"));
    v.push_back(new Music("Blowing in the wind", "Bob Dylan"));

    for (Publisher* ptr : v) {
        ptr->publish();
        ptr->use();
        std::cout << '\n';
        delete ptr;
    }
}

void test2() {
    std::vector<std::unique_ptr<Publisher>> v;

    v.push_back(std::make_unique<Book>("Harry Potter", "J.K. Rowling"));
    v.push_back(std::make_unique<Film>("The Godfather", "Francis Ford Coppola"));
    v.push_back(std::make_unique<Music>("Blowing in the wind", "Bob Dylan"));

    for (const auto& ptr : v) {
        ptr->publish();
        ptr->use();
        std::cout << '\n';
    }
}

void test3() {
    Book book("A Philosophy of Software Design", "John Ousterhout");
    book.publish();
    book.use();
}

int main() {
    std::cout << "运行时多态：纯虚函数、抽象类\n";

    std::cout << "\n测试1: 使用原始指针\n";
    test1();

    std::cout << "\n测试2: 使用智能指针\n";
    test2();

    std::cout << "\n测试3: 直接使用类\n";
    test3();
}

 

1.1 包含纯虚函数。

virtual void publish() const = 0;         // 纯虚函数，作为接口继承
  virtual void use() const = 0;           // 纯虚函数，作为接口继承

1.2不能，纯虚函数不能直接实例化。

2.1  publish()     use()    

void publish() const override;     // 接口
  void use() const override;       // 接口

2.2

 3.1Publisher*,

3.2 Book Film Music

3.3 使派生类析构函数正常调用，避免内存泄漏；

内存泄漏

二

 

#pragma once
#include <string>
// 图书描述信息类Book: 声明
class Book {
public:
    Book(const std::string& name_,
        const std::string& author_,
        const std::string& translator_,
        const std::string& isbn_,
        double price_);
    friend std::ostream& operator<<(std::ostream& out, const Book& book);
private:
    std::string name;// 书名
    std::string author;// 作者
    std::string translator;// 译者
    std::string isbn;// isbn号
    double price;// 定价
};
#pragma once
#include <string>
#include "book.hpp"
// 图书销售记录类BookSales：声明
class BookSale {
public:
    BookSale(const Book& rb_, double sales_price_, int sales_amount_);
    int get_amount() const;// 返回销售数量
    double get_revenue() const;// 返回营收

    friend std::ostream& operator<<(std::ostream& out, const BookSale& item);
private:
    Book rb;
    double sales_price;// 售价
    int sales_amount;// 销售数量
};
#include <iomanip>
#include <iostream>
#include <string>
#include "book.hpp"
// 图书描述信息类Book: 实现
Book::Book(const std::string& name_,
    const std::string& author_,
    const std::string& translator_,
    const std::string& isbn_,
    double price_) :name{ name_ }, author{ author_ }, translator{ translator_ },
    isbn{ isbn_ }, price{ price_ } {
}
// 运算符<<重载实现
std::ostream& operator<<(std::ostream& out, const Book& book) {
    using std::left;
    using std::setw;

    out << left;
    out << setw(15) << "书名:" << book.name << '\n'
        << setw(15) << "作者:" << book.author << '\n'
        << setw(15) << "译者:" << book.translator << '\n'
        << setw(15) << "ISBN:" << book.isbn << '\n'
        << setw(15) << "定价:" << book.price;
    return out;
}
#include <iomanip>
#include <iostream>
#include <string>
#include "booksale.hpp"
// 图书销售记录类BookSales：实现
BookSale::BookSale(const Book& rb_,
    double sales_price_,
    int sales_amount_) : rb{ rb_ }, sales_price{ sales_price_ },
    sales_amount{ sales_amount_ } {
}
int BookSale::get_amount() const {
    return sales_amount;
}
double BookSale::get_revenue() const {
    return sales_amount * sales_price;
}
// 运算符<<重载实现
std::ostream& operator<<(std::ostream& out, const BookSale& item) {
    using std::left;
    using std::setw;

    out << left;
    out << item.rb << '\n'
        << setw(15) << "售价:" << item.sales_price << '\n'
        << setw(15) << "销售数量:" << item.sales_amount << '\n'
        << setw(15) << "营收:" << item.get_revenue();
    return out;
}
#include "booksale.hpp"
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
// 按图书销售数额比较
bool compare_by_amount(const BookSale& x1, const BookSale& x2) {
    return x1.get_amount() > x2.get_amount();
}
void test() {
    using namespace std;
    vector<BookSale> sales_lst;// 存放图书销售记录
    int books_number;
    cout << "录入图书数量: ";
    cin >> books_number;
    cout << "录入图书销售记录" << endl;
    for (int i = 0; i < books_number; ++i) {
        string name, author, translator, isbn;
        float price;
        cout << string(20, '-') << "第" << i + 1 << "本图书信息录入" << string(20, '-') <<
            endl;
        cout << "录入书名: "; cin >> name;
        cout << "录入作者: "; cin >> author;
        cout << "录入译者: "; cin >> translator;
        cout << "录入isbn: "; cin >> isbn;
        cout << "录入定价: "; cin >> price;
        Book book(name, author, translator, isbn, price);
        float sales_price;
        int sales_amount;
        cout << "录入售价: "; cin >> sales_price;
        cout << "录入销售数量: "; cin >> sales_amount;
        BookSale record(book, sales_price, sales_amount);
        sales_lst.push_back(record);
    }
    // 按销售册数排序
    sort(sales_lst.begin(), sales_lst.end(), compare_by_amount);
    // 按销售册数降序输出图书销售信息
    cout << string(20, '=') << "图书销售统计" << string(20, '=') << endl;
    for (auto& t : sales_lst) {
        cout << t << endl;
        cout << string(40, '-') << endl;
    }
}
int main() {
    test();
}

1.1两处，BookSale，Book

1.2 

for (auto& t : sales_lst) {
cout << t << endl;
cout << string(40, '-') << endl;
}

2.1sort(sales_lst.begin(), sales_lst.end(), compare_by_amount);// 按销售册数排序

 

三

 

#include <iostream>
// 类A的定义
class A {
public:
    A(int x0, int y0);
    void display() const;
private:
    int x, y;
};
A::A(int x0, int y0) : x{ x0 }, y{ y0 } {
}
void A::display() const {
    std::cout << x << ", " << y << '\n';
}
// 类B的定义
class B {
public:
    B(double x0, double y0);
    void display() const;
private:
    double x, y;
};
B::B(double x0, double y0) : x{ x0 }, y{ y0 } {
}
void B::display() const {
    std::cout << x << ", " << y << '\n';
}
void test() {
    std::cout << "测试类A: " << '\n';
    A a(3, 4);
    a.display();
    std::cout << "\n测试类B: " << '\n';
    B b(3.2, 5.6);
    b.display();
}
int main() {
    test();
}

 

#include <iostream>
#include <string>
// 定义类模板
template<typename T>
class X {
public:
    X(T x0, T y0);
    void display();
private:
    T x, y;
};
template<typename T>
X<T>::X(T x0, T y0) : x{ x0 }, y{ y0 } {
}
template<typename T>
void X<T>::display() {
    std::cout << x << ", " << y << '\n';
}
void test() {
    std::cout << "测试1: 用int实例化类模板X" << '\n';
    X<int> x1(3, 4);
    x1.display();
    std::cout << "\n测试2: 用double实例化类模板X" << '\n';
    X<double> x2(3.2, 5.6);
    x2.display();
    std::cout << "\n测试3: 用string实例化类模板X" << '\n';
    X<std::string> x3("hello", "oop");
    x3.display();
}
int main() {
    test();
}

 

四

 

#pragma once
#include<string>
#include <iostream>

class MachinePet
{private:
    std::string nickname;
public:
    MachinePet(std::string name)
    {
        nickname = name;
    }

    std::string get_nickname()const
    {
        return nickname;
    }
    virtual std::string talk() = 0;
};
class PetDog :public MachinePet
{
public:
    PetDog(const std::string& name_):MachinePet(name_)
    {
    }
    std::string talk()
    {
        return "dog";
    }
};

class PetCat :public MachinePet
{
public:
    PetCat(const std::string& name_):MachinePet(name_)
    {
        
    }
    std::string talk()
    {
        return "cat";
    }
};
std::ostream& operator<<(std::ostream& cout, const std::string& name)
{
    if(name=="dog")
    cout << "wang wang";
    if(name=="cat")
        cout << "miao wu~";
    return cout;
}


#include <iostream>
#include <memory>
#include <vector>
#include "pet.hpp"
void test1() {
    std::vector<MachinePet*> pets;
    pets.push_back(new PetCat("miku"));
    pets.push_back(new PetDog("da huang"));
    for (MachinePet* ptr : pets) {
        std::cout << ptr->get_nickname() << " says " << ptr->talk() << '\n';
        delete ptr;// 须手动释放资源
    }
}
void test2() {
    std::vector<std::unique_ptr<MachinePet>> pets;
    pets.push_back(std::make_unique<PetCat>("miku"));
    pets.push_back(std::make_unique<PetDog>("da huang"));
    for (auto const& ptr : pets)
        std::cout << ptr->get_nickname() << " says " << ptr->talk() << '\n';
}
void test3() {
    // MachinePet pet("little cutie");   // 编译报错：无法定义抽象类对象
     PetCat cat("miku");
    std::cout << cat.get_nickname() << " says " << cat.talk() << '\n';
     PetDog dog("da huang");
    std::cout << dog.get_nickname() << " says " << dog.talk() << '\n';
}
int main() {
    std::cout << "测试1: 使用原始指针\n";
    test1();
    std::cout << "\n测试2: 使用智能指针\n";
    test2();
    std::cout << "\n测试3: 直接使用类\n";
    test3();
}

 

 五

 

#pragma once
#include<iostream>
#include<string>

template<typename T>
class Complex
{
public:
    template<typename U>
    friend std::istream& operator>>(std::istream& cin, Complex<U>& c);
    Complex<T>& operator+=(const Complex<T>& c2) {
        this->real += c2.real;
        this->imag += c2.imag;
        return *this;
    }
    Complex()
    {
        real = 0;
        imag = 0;
    }
    Complex(T r, T i)
    {
        real = r;
        imag = i;
    }
    T get_real()const
    {
        return real;
    }
    T get_imag()const
    {
        return imag;
    }
private:
    T real;
    T imag;
};
template <typename T>
std::ostream& operator<<(std::ostream& cout, const Complex<T>& c)
{
    if (c.get_imag() >= 0)
        cout << c.get_real() << "+" << c.get_imag() << "i";
    else
        cout << c.get_real() << "-" << (-1) * c.get_imag() << "i";
    return cout;
}
template <typename T>
 Complex<T> operator+(const Complex<T>& c1, const Complex<T>& c2)
{


    Complex<T> c3 = c1; // 利用拷贝构造
    c3 += c2;           // 复用operator+=，减少冗余
    return c3;
}

template <typename T>
bool operator==(const Complex<T>& c1, const Complex<T>& c2)
{
    if (c1.get_real() == c2.get_real() && c1.get_imag() == c2.get_imag())
        return true;
    else
        return false;
}
template <typename T>
std::istream& operator>>(std::istream& cin, Complex<T>& c)
{
    cin >> c.real >> c.imag;
    return cin;
}