实验5

温州机场航鹏翔空货运 發表於 2025-12-16 23:52:00

实验任务1：
代码：
publisher.cpp
<div class="cnblogs_code">
<pre> 1 #include <iostream>
 2 #include <string>
 3 #include "publisher.hpp"
 4
 5 Publisher::Publisher(const std::string &name_): name {name_} {
 6 }
 7
 8
 9 Book::Book(const std::string &name_ , const std::string &author_ ): Publisher{name_}, author{author_} {
10 }
11
12 void Book::publish() const {
13 std::cout << "Publishing book《" << name << "》 by " << author << '\n';
14 }
15
16 void Book::use() const {
17 std::cout << "Reading book 《" << name << "》 by " << author << '\n';
18 }
19
20
21 Film::Film(const std::string &name_, const std::string &director_):Publisher{name_},director{director_} {
22 }
23
24 void Film::publish() const {
25 std::cout << "Publishing film <" << name << "> directed by " << director << '\n';
26 }
27
28 void Film::use() const {
29 std::cout << "Watching film <" << name << "> directed by " << director << '\n';
30 }
31
32
33 Music::Music(const std::string &name_, const std::string &artist_): Publisher{name_}, artist{artist_} {
34 }
35
36 void Music::publish() const {
37 std::cout << "Publishing music <" << name << "> by " << artist << '\n';
38 }
39
40 void Music::use() const {
41 std::cout << "Listening to music <" << name << "> by " << artist << '\n';
42 }</pre>
</div>
publisher.hpp
<div class="cnblogs_code">
<pre> 1 #pragma once
 2
 3 #include <string>
 4
 5 class Publisher {
 6 public:
 7 Publisher(const std::string &name_ = "");
 8 virtual ~Publisher() = default;
 9
10 public:
11 virtual void publish() const = 0; // 纯虚函数，作为接口继承
12 virtual void use() const = 0; // 纯虚函数，作为接口继承
13
14 protected:
15 std::string name; // 发行/出版物名称
16 };
17
18 // 图书类: Book
19 class Book: public Publisher {
20 public:
21 Book(const std::string &name_ = "", const std::string &author_ = "");// 构造函数
22
23 public:
24 void publish() const override; // 接口
25 void use() const override; // 接口
26
27 private:
28 std::string author; // 作者
29 };
30
31 // 电影类: Film
32 class Film: public Publisher {
33 public:
34 Film(const std::string &name_ = "", const std::string &director_ = ""); // 构造函数
35
36 public:
37 void publish() const override; // 接口
38 void use() const override; // 接口 
39
40 private:
41 std::string director; // 导演
42 };
43
44
45 // 音乐类：Music
46 class Music: public Publisher {
47 public:
48 Music(const std::string &name_ = "", const std::string &artist_ = "");
49
50 public:
51 void publish() const override; // 接口
52 void use() const override; // 接口
53
54 private:
55 std::string artist; // 音乐艺术家名称
56 };</pre>
</div>
task1.cpp
<div class="cnblogs_code">
<pre> 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 }</pre>
</div>
运行测试截图：
<img src="https://img2024.cnblogs.com/blog/3526577/202512/3526577-20251216193756762-954707300.png">
回答问题：
问题1：
（1）Publisher类中包含纯虚函数。具体依据：virtual void publish() const = 0;和virtual void use() const = 0；
（2）不能编译通过。因为抽象类不能实例化对象。
问题2：
（1）void publish() const override;
void use() const override;
（2）函数签名与基类不匹配，无法重写
问题3：
（1）ptr的声明类型是Publisher*
（2）Book, Film, Music
（3）原因：实现多态析构，确保删除派生类对象时，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,派生类的析构函数不被调用，内存泄漏。
 
实验任务2：
代码：
book.hpp
<div class="cnblogs_code">
<pre> 1 #pragma once
 2 #include <string>
 3
 4 // 图书描述信息类Book: 声明
 5 class Book {
 6 public:
 7 Book(const std::string &name_,
 8 const std::string &author_,
 9 const std::string &translator_,
10 const std::string &isbn_,
11 double price_);
12
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 };</pre>
</div>
book.cpp
<div class="cnblogs_code">
<pre> 1 #include <iomanip>
 2 #include <iostream>
 3 #include <string>
 4 #include "book.hpp"
 5
 6
 7 // 图书描述信息类Book: 实现
 8 Book::Book(const std::string &name_,
 9 const std::string &author_,
10 const std::string &translator_,
11 const std::string &isbn_,
12 double price_):name{name_}, author{author_}, translator{translator_}, isbn{isbn_}, price{price_} {
13 }
14
15 // 运算符<<重载实现
16 std::ostream& operator<<(std::ostream &out, const Book &book) {
17 using std::left;
18 using std::setw;
19
20 out << left;
21 out << setw(15) << "书名:" << book.name << '\n'
22 << setw(15) << "作者:" << book.author << '\n'
23 << setw(15) << "译者:" << book.translator << '\n'
24 << setw(15) << "ISBN:" << book.isbn << '\n'
25 << setw(15) << "定价:" << book.price;
26
27 return out;
28 }</pre>
</div>
booksale.hpp
<div class="cnblogs_code">
<pre> 1 #pragma once
 2
 3 #include <string>
 4 #include "book.hpp"
 5
 6 // 图书销售记录类BookSales：声明
 7 class BookSale {
 8 public:
 9 BookSale(const Book &rb_, double sales_price_, int sales_amount_);
10 int get_amount() const; // 返回销售数量
11 double get_revenue() const; // 返回营收
12
13 friend std::ostream& operator<<(std::ostream &out, const BookSale &item);
14
15 private:
16 Book rb;
17 double sales_price; // 售价
18 int sales_amount; // 销售数量
19 };</pre>
</div>
booksale.cpp
<div class="cnblogs_code">
<pre> 1 #include <iomanip>
 2 #include <iostream>
 3 #include <string>
 4 #include "booksale.hpp"
 5
 6 // 图书销售记录类BookSales：实现
 7 BookSale::BookSale(const Book &rb_,
 8 double sales_price_,
 9 int sales_amount_): rb{rb_}, sales_price{sales_price_}, sales_amount{sales_amount_} {
10 }
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
25 out << left;
26 out << item.rb << '\n'
27 << setw(15) << "售价:" << item.sales_price << '\n'
28 << setw(15) << "销售数量:" << item.sales_amount << '\n'
29 << setw(15) << "营收:" << item.get_revenue();
30
31 return out;
32 }</pre>
</div>
task2.cpp
<div class="cnblogs_code">
<pre> 1 #include <algorithm>
 2 #include <iomanip>
 3 #include <iostream>
 4 #include <string>
 5 #include <vector>
 6 #include "booksale.hpp"
 7
 8 // 按图书销售数量比较
 9 bool compare_by_amount(const BookSale &x1, const BookSale &x2) {
10 return x1.get_amount() > x2.get_amount();
11 }
12
13 void test() {
14 using std::cin;
15 using std::cout;
16 using std::getline;
17 using std::sort;
18 using std::string;
19 using std::vector;
20 using std::ws;
21
22 vector<BookSale> sales_records; // 图书销售记录表
23
24 int books_number;
25 cout << "录入图书数量: ";
26 cin >> books_number;
27
28 cout << "录入图书销售记录\n";
29 for(int i = 0; i < books_number; ++i) {
30 string name, author, translator, isbn;
31 double price;
32 cout << string(20, '-') << "第" << i+1 << "本图书信息录入" << string(20, '-') << '\n';
33 cout << "录入书名: "; getline(cin>>ws, name);
34 cout << "录入作者: "; getline(cin>>ws, author);
35 cout << "录入译者: "; getline(cin>>ws, translator);
36 cout << "录入isbn: "; getline(cin>>ws, isbn);
37 cout << "录入定价: "; cin >> price;
38
39 Book book(name, author, translator, isbn, price);
40
41 double sales_price;
42 int sales_amount;
43
44 cout << "录入售价: "; cin >> sales_price;
45 cout << "录入销售数量: "; cin >> sales_amount;
46
47 BookSale record(book, sales_price, sales_amount);
48 sales_records.push_back(record);
49 }
50
51 // 按销售册数排序
52 sort(sales_records.begin(), sales_records.end(), compare_by_amount);
53
54 // 按销售册数降序输出图书销售信息
55 cout << string(20, '=') <<"图书销售统计" << string(20, '=') << '\n';
56 for(auto &record: sales_records) {
57 cout << record << '\n';
58 cout << string(40, '-') << '\n';
59 }
60 }
61
62 int main() {
63 test();
64 }</pre>
</div>
运行测试截图：
<img src="https://img2024.cnblogs.com/blog/3526577/202512/3526577-20251216221348249-1141424125.png">
 回答问题：
问题1：
（1）两处。Book类型和BookSale类型
（2）book.cpp中：std::ostream& operator<<(std::ostream &out, const Book &book);
booksale.cpp中：std::ostream& operator<<(std::ostream &out, const BookSale &item);
task2.cpp中：cout << t <<endl;
问题2：
（1）使用 std::sort 函数，配合自定义比较函数 compare_by_amount
 
实验任务4：
pet.hpp
<div class="cnblogs_code">
<pre> 1 #pragma once
 2 #include <string>
 3
 4 class MachinePet {
 5 public:
 6 MachinePet(const std::string& nickname_) : nickname(nickname_) {}
 7 virtual ~MachinePet() = default;
 8
 9 std::string get_nickname() const {
10 return nickname;
11 }
12
13 virtual std::string talk() const = 0;
14
15 protected:
16 std::string nickname;
17 };
18
19 class PetCat : public MachinePet {
20 public:
21 PetCat(const std::string& nickname_) : MachinePet(nickname_) {}
22
23 std::string talk() const override {
24 return "miao wu~";
25 }
26 };
27
28 class PetDog : public MachinePet {
29 public:
30 PetDog(const std::string& nickname_) : MachinePet(nickname_) {}
31
32 std::string talk() const override {
33 return "wang wang~";
34 }
35 };</pre>
</div>
task4.cpp
<div class="cnblogs_code">
<pre> 1 #include <iostream>
 2 #include <memory>
 3 #include <vector>
 4 #include "pet.hpp"
 5
 6 void test1() {
 7 std::vector<MachinePet *> pets;
 8
 9 pets.push_back(new PetCat("miku"));
10 pets.push_back(new PetDog("da huang"));
11
12 for(MachinePet *ptr: pets) {
13 std::cout << ptr->get_nickname() << " says " << ptr->talk() << '\n';
14 delete ptr;// 须手动释放资源
15 }
16 }
17
18 void test2() {
19 std::vector<std::unique_ptr<MachinePet>> pets;
20
21 pets.push_back(std::make_unique<PetCat>("miku"));
22 pets.push_back(std::make_unique<PetDog>("da huang"));
23
24 for(auto const &ptr: pets)
25 std::cout << ptr->get_nickname() << " says " << ptr->talk() << '\n';
26 }
27
28 void test3() {
29 // MachinePet pet("little cutie"); // 编译报错：无法定义抽象类对象
30
31 const PetCat cat("miku");
32 std::cout << cat.get_nickname() << " says " << cat.talk() << '\n';
33
34 const PetDog dog("da huang");
35 std::cout << dog.get_nickname() << " says " << dog.talk() << '\n';
36 }
37
38 int main() {
39 std::cout << "测试1: 使用原始指针\n";
40 test1();
41
42 std::cout << "\n测试2: 使用智能指针\n";
43 test2();
44
45 std::cout << "\n测试3: 直接使用类\n";
46 test3();
47 }</pre>
</div>
运行测试截图：
<img src="https://img2024.cnblogs.com/blog/3526577/202512/3526577-20251216235125412-2117472521.png">
 
实验任务5：
Complex.hpp
<div class="cnblogs_code">
<pre> 1 #pragma once
 2 #include <iostream>
 3
 4 template<typename T>
 5 class Complex {
 6 private:
 7 T real;
 8 T imag;
 9
10 public:
11 Complex() : real(0), imag(0) {}
12 Complex(T real_, T imag_) : real(real_), imag(imag_) {}
13 Complex(const Complex &other) : real(other.real), imag(other.imag) {}
14
15 T get_real() const { return real; }
16 T get_imag() const { return imag; }
17
18 Complex &operator+=(const Complex &other) {
19 real += other.real;
20 imag += other.imag;
21 return *this;
22 }
23
24 friend Complex operator+(const Complex &c1, const Complex &c2) {
25 Complex temp = c1;
26 temp += c2;
27 return temp;
28 }
29
30 friend bool operator==(const Complex &c1, const Complex &c2) {
31 return c1.real == c2.real && c1.imag == c2.imag;
32 }
33
34 friend std::ostream &operator<<(std::ostream &out, const Complex &c) {
35 out << c.real;
36 if (c.imag >= 0) {
37 out << "+" << c.imag << "i";
38 } else {
39 out << c.imag << "i";
40 }
41 return out;
42 }
43
44 friend std::istream &operator>>(std::istream &in, Complex &c) {
45 in >> c.real >> c.imag;
46 return in;
47 }
48
49 };</pre>
</div>
task5.cpp
<div class="cnblogs_code">
<pre> 1 #include <iostream>
 2 #include "Complex.hpp"
 3
 4 void test1() {
 5 using std::cout;
 6 using std::boolalpha;
 7
 8 Complex<int> c1(2, -5), c2(c1);
 9
10 cout << "c1 = " << c1 << '\n';
11 cout << "c2 = " << c2 << '\n';
12 cout << "c1 + c2 = " << c1 + c2 << '\n';
13
14 c1 += c2;
15 cout << "c1 = " << c1 << '\n';
16 cout << boolalpha << (c1 == c2) << '\n';
17 }
18
19 void test2() {
20 using std::cin;
21 using std::cout;
22
23 Complex<double> c1, c2;
24 cout << "Enter c1 and c2: ";
25 cin >> c1 >> c2;
26 cout << "c1 = " << c1 << '\n';
27 cout << "c2 = " << c2 << '\n';
28
29 const Complex<double> c3(c1);
30 cout << "c3.real = " << c3.get_real() << '\n';
31 cout << "c3.imag = " << c3.get_imag() << '\n';
32 }
33
34 int main() {
35 std::cout << "自定义类模板Complex测试1: \n";
36 test1();
37
38 std::cout << "\n自定义类模板Complex测试2: \n";
39 test2();
40 }</pre>
</div>
运行测试截图：
<img src="https://img2024.cnblogs.com/blog/3526577/202512/3526577-20251216235235953-1706928464.png">
  
来源：https://www.cnblogs.com/chenya17/p/19335061

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实验5