实验五

实验一：

 1 #include <memory>
 2 #include <iostream>
 3 #include <vector>
 4 #include "publisher.hpp"
 5 
 6 void test1() {
 7    std::vector<Publisher *> v;
 8 
 9    v.push_back(new Book("Harry Potter", "J.K. Rowling"));
10    v.push_back(new Film("The Godfather", "Francis Ford Coppola"));
11    v.push_back(new Music("Blowing in the wind", "Bob Dylan"));
12 
13    for(Publisher *ptr: v) {
14         ptr->publish();
15         ptr->use();
16         std::cout << '\n';
17         delete ptr;
18    }
19 }
20 
21 void test2() {
22     std::vector<std::unique_ptr<Publisher>> v;
23 
24     v.push_back(std::make_unique<Book>("Harry Potter", "J.K. Rowling"));
25     v.push_back(std::make_unique<Film>("The Godfather", "Francis Ford Coppola"));
26     v.push_back(std::make_unique<Music>("Blowing in the wind", "Bob Dylan"));
27 
28     for(const auto &ptr: v) {
29         ptr->publish();
30         ptr->use();
31         std::cout << '\n';
32     }
33 }
34 
35 void test3() {
36     Book book("A Philosophy of Software Design", "John Ousterhout");
37     book.publish();
38     book.use();
39 }
40 
41 int main() {
42     std::cout << "运行时多态：纯虚函数、抽象类\n";
43 
44     std::cout << "\n测试1: 使用原始指针\n";
45     test1();
46 
47     std::cout << "\n测试2: 使用智能指针\n";
48     test2();
49 
50     std::cout << "\n测试3: 直接使用类\n";
51     test3();
52 }
publisher.h
 1 #include <iostream>
 2 #include <string>
 3 #include "publisher.hpp"
 4 
 5 // Publisher类：实现
 6 Publisher::Publisher(const std::string &name_): name {name_} {
 7 }
 8 
 9 
10 // Book类: 实现
11 Book::Book(const std::string &name_ , const std::string &author_ ): Publisher{name_}, author{author_} {
12 }
13 
14 void Book::publish() const {
15     std::cout << "Publishing book《" << name << "》 by " << author << '\n';
16 }
17 
18 void Book::use() const {
19     std::cout << "Reading book 《" << name << "》 by " << author << '\n';
20 }
21 
22 
23 // Film类：实现
24 Film::Film(const std::string &name_, const std::string &director_):Publisher{name_},director{director_} {
25 }
26 
27 void Film::publish() const {
28     std::cout << "Publishing film <" << name << "> directed by " << director << '\n';
29 }
30 
31 void Film::use() const {
32     std::cout << "Watching film <" << name << "> directed by " << director << '\n';
33 }
34 
35 
36 // Music类：实现
37 Music::Music(const std::string &name_, const std::string &artist_): Publisher{name_}, artist{artist_} {
38 }
39 
40 void Music::publish() const {
41     std::cout << "Publishing music <" << name << "> by " << artist << '\n';
42 }
43 
44 void Music::use() const {
45     std::cout << "Listening to music <" << name << "> by " << artist << '\n';
46 }
publisher.cpp
 1 #include <memory>
 2 #include <iostream>
 3 #include <vector>
 4 #include "publisher.hpp"
 5 
 6 void test1() {
 7    std::vector<Publisher *> v;
 8 
 9    v.push_back(new Book("Harry Potter", "J.K. Rowling"));
10    v.push_back(new Film("The Godfather", "Francis Ford Coppola"));
11    v.push_back(new Music("Blowing in the wind", "Bob Dylan"));
12 
13    for(Publisher *ptr: v) {
14         ptr->publish();
15         ptr->use();
16         std::cout << '\n';
17         delete ptr;
18    }
19 }
20 
21 void test2() {
22     std::vector<std::unique_ptr<Publisher>> v;
23 
24     v.push_back(std::make_unique<Book>("Harry Potter", "J.K. Rowling"));
25     v.push_back(std::make_unique<Film>("The Godfather", "Francis Ford Coppola"));
26     v.push_back(std::make_unique<Music>("Blowing in the wind", "Bob Dylan"));
27 
28     for(const auto &ptr: v) {
29         ptr->publish();
30         ptr->use();
31         std::cout << '\n';
32     }
33 }
34 
35 void test3() {
36     Book book("A Philosophy of Software Design", "John Ousterhout");
37     book.publish();
38     book.use();
39 }
40 
41 int main() {
42     std::cout << "运行时多态：纯虚函数、抽象类\n";
43 
44     std::cout << "\n测试1: 使用原始指针\n";
45     test1();
46 
47     std::cout << "\n测试2: 使用智能指针\n";
48     test2();
49 
50     std::cout << "\n测试3: 直接使用类\n";
51     test3();
52 }
task1.cpp

运行截图：

 

image

 问题一：（1）：含有纯虚函数的类是抽象类，代码中Publisher类声明了virtual void publish() const = 0;和virtual void use() const = 0;两个纯虚函数，因此是抽象类。

（2）：不能编译通过。Publisher是抽象类，抽象类不能实例化对象，编译器会报错

问题二：（1）：void publish() const override;

　　　　　　  void use() const override;

（2）：

image

 问题三：（1）：Publisher*

（2)：Book、Film、Music

（3)：为了实现 “多态析构”，确保删除基类指针指向的派生类对象时，能先调用派生类析构函数，再调用基类析构函数，避免内存泄漏；若删除virtual，则析构函数不具备多态性，删除基类指针时仅调用基类析构函数，派生类的成员变量无法被正确释放，导致内存泄漏

实验二：

 1 #pragma once
 2 #include <string>
 3 #include <iostream>
 4 
 5 // 图书描述信息类Book: 声明
 6 class Book {
 7 public:
 8     Book(const std::string &name_,
 9          const std::string &author_,
10          const std::string &translator_,
11          const std::string &isbn_,
12          double price_);
13     friend std::ostream& operator<<(std::ostream &out, const Book &book);
14 
15 private:
16     std::string name; // 书名
17     std::string author; // 作者
18     std::string translator; // 译者
19     std::string isbn; // isbn号
20     double price; // 定价
21 };
book.hpp
 1 #include <<iomanip>
 2 #include <iostream>
 3 #include <string>
 4 #include "book.hpp"
 5 
 6 // 图书描述信息类Book: 实现
 7 Book::Book(const std::string &name_,
 8            const std::string &author_,
 9            const std::string &translator_,
10            const std::string &isbn_,
11            double price_) : name{name_}, author{author_}, translator{translator_},
12                             isbn{isbn_}, price{price_} {}
13 
14 // 运算符<<重载实现
15 std::ostream& operator<<(std::ostream &out, const Book &book) {
16     using std::left;
17     using std::setw;
18     out << left;
19     out << setw(15) << "书名:" << book.name << '\n'
20         << setw(15) << "作者:" << book.author << '\n'
21         << setw(15) << "译者:" << book.translator << '\n'
22         << setw(15) << "ISBN:" << book.isbn << '\n'
23         << setw(15) << "定价:" << book.price;
24     return out;
25 }
book.cpp
 1 #pragma once
 2 #include <string>
 3 #include "book.hpp"
 4 
 5 // 图书销售记录类BookSale:声明
 6 class BookSale {
 7 public:
 8     BookSale(const Book &rb_, double sales_price_, int sales_amount_);
 9     int get_amount() const; // 返回销售数量
10     double get_revenue() const; // 返回营收
11     friend std::ostream& operator<<(std::ostream &out, const BookSale &item);
12 
13 private:
14     Book rb; // 图书对象
15     double sales_price; // 售价
16     int sales_amount; // 销售数量
17 };
booksale.hpp
 1 #include <<iomanip>
 2 #include <iostream>
 3 #include <string>
 4 #include "booksale.hpp"
 5 
 6 // 图书销售记录类BookSale:实现
 7 BookSale::BookSale(const Book &rb_,
 8                    double sales_price_,
 9                    int sales_amount_) : rb{rb_}, sales_price{sales_price_},
10                                         sales_amount{sales_amount_} {}
11 
12 int BookSale::get_amount() const {
13     return sales_amount;
14 }
15 
16 double BookSale::get_revenue() const {
17     return sales_amount * sales_price;
18 }
19 
20 // 运算符<<重载实现
21 std::ostream& operator<<(std::ostream &out, const BookSale &item) {
22     using std::left;
23     using std::setw;
24     out << left;
25     out << item.rb << '\n'
26         << setw(15) << "售价:" << item.sales_price << '\n'
27         << setw(15) << "销售数量:" << item.sales_amount << '\n'
28         << setw(15) << "营收:" << item.get_revenue();
29     return out;
30 }
booksale.cpp
 1 #include "booksale.hpp"
 2 #include <iostream>
 3 #include <string>
 4 #include <vector>
 5 #include <algorithm>
 6 
 7 // 按图书销售数额比较（降序）
 8 bool compare_by_amount(const BookSale &x1, const BookSale &x2) {
 9     return x1.get_amount() > x2.get_amount();
10 }
11 
12 void test() {
13     using namespace std;
14     vector<BookSale> sales_lst; // 存放图书销售记录
15     int books_number;
16     cout << "录入图书数量: ";
17     cin >> books_number;
18     cout << "录入图书销售记录" << endl;
19     for (int i = 0; i < books_number; ++i) {
20         string name, author, translator, isbn;
21         float price;
22         cout << string(20, '-') << "第" << i + 1 << "本图书信息录入" << string(20, '-') << endl;
23         cout << "录入书名: ";
24         cin >> name;
25         cout << "录入作者: ";
26         cin >> author;
27         cout << "录入译者: ";
28         cin >> translator;
29         cout << "录入isbn: ";
30         cin >> isbn;
31         cout << "录入定价: ";
32         cin >> price;
33         Book book(name, author, translator, isbn, price);
34         float sales_price;
35         int sales_amount;
36         cout << "录入售价: ";
37         cin >> sales_price;
38         cout << "录入销售数量: ";
39         cin >> sales_amount;
40         BookSale record(book, sales_price, sales_amount);
41         sales_lst.push_back(record);
42     }
43     // 按销售册数排序
44     sort(sales_lst.begin(), sales_lst.end(), compare_by_amount);
45     // 按销售册数降序输出图书销售信息
46     cout << string(20, '=') << "图书销售统计" << string(20, '=') << endl;
47     for (auto &t : sales_lst) {
48         cout << t << endl;
49         cout << string(40, '-') << endl;
50     }
51 }
52 
53 int main() {
54     test();
55 }
task2.cpp

运行截图：

image

 问题一：（1）：重载了 2 处，分别用于Book类型和BookSale类型

（2）：out << item.rb << '\n';

　　    cout << t << endl;

　　    out << setw(15) << "书名:" << book.name << '\n' 

问题二：（1）：首先定义比较函数compare_by_amount，该函数接收两个 对象，返回 “第一个对象的销售数量大于第二个对象” 的布尔值；然后调用标准库sort函数，传入销售记录向量的起始、结束和比较函数，sort函数会对元素进行降序排序。

（2）：sort(sales_lst.begin(), sales_lst.end(), [](const BookSale &x1, const BookSale &x2){

　　　　return x1.get_amount() > x2.get_amount();

　　　});

实验三：

 1 #include <iostream>
 2 
 3 // 类A的定义（数据成员为int类型）
 4 class A {
 5 public:
 6     A(int x0, int y0);
 7     void display() const;
 8 private:
 9     int x, y;
10 };
11 
12 // 类A构造函数实现
13 A::A(int x0, int y0) : x{x0}, y{y0} {
14 }
15 
16 // 类A成员函数display实现
17 void A::display() const {
18     std::cout << x << ", " << y << '\n';
19 }
20 
21 // 类B的定义（数据成员为double类型）
22 class B {
23 public:
24     B(double x0, double y0);
25     void display() const;
26 private:
27     double x, y;
28 };
29 
30 // 类B构造函数实现
31 B::B(double x0, double y0) : x{x0}, y{y0} {
32 }
33 
34 // 类B成员函数display实现
35 void B::display() const {
36     std::cout << x << ", " << y << '\n';
37 }
38 
39 // 测试函数
40 void test() {
41     std::cout << "测试类A: " << '\n';
42     A a(3, 4);
43     a.display();
44 
45     std::cout << "\n测试类B: " << '\n';
46     B b(3.2, 5.6);
47     b.display();
48 }
49 
50 // 主函数
51 int main() {
52     test();
53 }
task3_1.cpp
 1 #include <iostream>
 2 #include <string>
 3 
 4 // 定义类模板X（类型参数T）
 5 template<typename T>
 6 class X {
 7 public:
 8     X(T x0, T y0);
 9     void display();
10 private:
11     T x, y; // 数据成员类型由模板参数T指定
12 };
13 
14 // 类模板X的构造函数实现（类外实现需加模板头）
15 template<typename T>
16 X<T>::X(T x0, T y0) : x{x0}, y{y0} {
17 }
18 
19 // 类模板X的成员函数display实现（类外实现需加模板头）
20 template<typename T>
21 void X<T>::display() {
22     std::cout << x << ", " << y << '\n';
23 }
24 
25 // 测试函数（实例化不同类型的类模板X）
26 void test() {
27     std::cout << "测试1: 用int实例化类模板X" << '\n';
28     X<int> x1(3, 4);
29     x1.display();
30 
31     std::cout << "\n测试2: 用double实例化类模板X" << '\n';
32     X<double> x2(3.2, 5.6);
33     x2.display();
34 
35     std::cout << "\n测试3: 用string实例化类模板X" << '\n';
36     X<std::string> x3("hello", "oop");
37     x3.display();
38 }
39 
40 // 主函数
41 int main() {
42     test();
43 }
task3_2.cpp

运行截图：

image

 

image

 实验四：

 1 #pragma once
 2 #include <string>
 3 
 4 class MachinePet {
 5 public:
 6    
 7     MachinePet(const std::string& nickname_) : nickname(nickname_) {}
 8     virtual ~MachinePet() = default;
 9     std::string get_nickname() const { return nickname; }
10     virtual std::string talk() const = 0;
11 
12 protected:
13     std::string nickname; 
14 };
15 
16 class PetCat : public MachinePet {
17 public:
18     PetCat(const std::string& nickname_) : MachinePet(nickname_) {}
19     std::string talk() const override { return "miao wu~"; }
20 };
21 
22 class PetDog : public MachinePet {
23 public:
24     PetDog(const std::string& nickname_) : MachinePet(nickname_) {}
25     std::string talk() const override { return "wang wang~"; }
26 };
pet.hpp
 1 #include <iostream>
 2 #include <memory>
 3 #include <vector>
 4 #include "pet.hpp"
 5 void test1() {
 6     std::vector<MachinePet*> pets;
 7     pets.push_back(new PetCat("miku"));
 8     pets.push_back(new PetDog("da huang"));
 9     for (MachinePet* ptr : pets) {
10         std::cout << ptr->get_nickname() << " says " << ptr->talk() << '\n';
11         delete ptr;
12     }
13 }
14 void test2() {
15     std::vector<std::unique_ptr<MachinePet>> pets;
16     pets.push_back(std::make_unique<PetCat>("miku"));
17     pets.push_back(std::make_unique<PetDog>("da huang"));
18     for (auto const& ptr : pets)
19         std::cout << ptr->get_nickname() << " says " << ptr->talk() << '\n';
20 }
21 void test3() {
22     // MachinePet pet("little cutie");   // 编译报错：无法定义抽象类对象
23     const PetCat cat("miku");
24     std::cout << cat.get_nickname() << " says " << cat.talk() << '\n';
25     const PetDog dog("da huang");
26     std::cout << dog.get_nickname() << " says " << dog.talk() << '\n';
27 }
28 int main() {
29     std::cout << "测试1: 使用原始指针\n";
30     test1();
31     std::cout << "\n测试2: 使用智能指针\n";
32     test2();
33     std::cout << "\n测试3: 直接使用类\n";
34     test3();
35 }
task4.cpp

运行截图：

image

 实验五：

 1 #pragma once
 2 #include <iostream>
 3 
 4 template<typename T>
 5 class Complex {
 6 public:
 7     Complex() : real(0), imag(0) {}
 8     Complex(T real_, T imag_) : real(real_), imag(imag_) {}
 9     Complex(const Complex& other) : real(other.real), imag(other.imag) {}
10 
11     T get_real() const { return real; }
12     T get_imag() const { return imag; }
13 
14     Complex& operator+=(const Complex& other) {
15         real += other.real;
16         imag += other.imag;
17         return *this;
18     }
19 
20     friend Complex operator+(const Complex& c1, const Complex& c2) {
21         return Complex(c1.real + c2.real, c1.imag + c2.imag);
22     }
23 
24     bool operator==(const Complex& other) const {
25         return (real == other.real) && (imag == other.imag);
26     }
27 
28     friend std::ostream& operator<<(std::ostream& out, const Complex& c) {
29         out << c.real;
30         if (c.imag >= 0) {
31             out << "+" << c.imag << "i";
32         }
33         else {
34             out << c.imag << "i";
35         }
36         return out;
37     }
38 
39     friend std::istream& operator>>(std::istream& in, Complex& c) {
40         in >> c.real >> c.imag;
41         return in;
42     }
43 
44 private:
45     T real;
46     T imag;
47 };
Complex.hpp
 1 #include <iostream>
 2 #include "Complex.hpp"
 3 void test1() {
 4     using std::cout;
 5     using std::boolalpha;
 6 
 7     Complex<int> c1(2, -5), c2(c1);
 8     cout << "c1 = " << c1 << '\n';
 9     cout << "c2 = " << c2 << '\n';
10     cout << "c1 + c2 = " << c1 + c2 << '\n';
11 
12     c1 += c2;
13     cout << "c1 = " << c1 << '\n';
14     cout << boolalpha << (c1 == c2) << '\n';
15 }
16 void test2() {
17     using std::cin;
18     using std::cout;
19     Complex<double> c1, c2;
20     cout << "Enter c1 and c2: ";
21     cin >> c1 >> c2;
22     cout << "c1 = " << c1 << '\n';
23     cout << "c2 = " << c2 << '\n';
24     const Complex<double> c3(c1);
25     cout << "c3.real = " << c3.get_real() << '\n';
26     cout << "c3.imag = " << c3.get_imag() << '\n';
27 }
28 int main() {
29     std::cout << "自定义类模板Complex测试1: \n";
30     test1();
31     std::cout << "\n自定义类模板Complex测试2: \n";
32     test2();
33 }
task5.cpp

运行截图：

image

 

posted @ 2025-12-16 19:24  yahuao  阅读(3)  评论(0)    收藏  举报