实验任务1
源代码 publisher.hpp,publisher.cpp,task1.cpp
点击查看代码 publisher.hpp
#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
};
点击查看代码 publisher.cpp
#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';
}
点击查看代码 task1.cpp
#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();
}
运行测试截图
-
问题1：抽象类机制
-
（1）是什么决定了
Publisher是抽象类？用一句话说明，并指出代码中的具体依据。 -
回答：纯虚函数决定了
Publisher是抽象类。可依据以下代码。
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
-
（2）如果在
main.cpp里直接写Publisher p;能否编译通过？为什么？ -
回答：不能编译通过。因为抽象类不能被实例化。
-
问题2：纯虚函数与接口继承
-
（1）
Book、Film、Music必须实现哪两个函数才能通过编译？请写出其完整函数声明。 -
回答：
publish和use函数。完整声明如下。
void publish() const override; // 接口void use() const override; // 接口
-
（2）在
publisher.cpp的Film类实现中，把两个成员函数实现里的const去掉（保持函数体不变），重新编译，报错信息是什么？ -
回答：无匹配的函数声明。
-
问题3：运行时多态与虚析构
-
（1）在
test1()里，for (Publisher *ptr : v)中ptr的声明类型是什么？ -
回答：
Publisher*。 -
（2）当循环执行到
ptr->publish();时，ptr实际指向的对象类型分别有哪些？（按循环顺序写出） -
回答：
Book、Film、Music。 -
（3）基类
Publisher的析构函数为何声明为virtual？若删除virtual，执行delete ptr;会出现什么问题？ -
回答：确保通过基类指针删除派生类对象时，能够正确调用派生类的析构函数。若删除
virtual，执行delete ptr;，会造成派生类资源未被正确释放。
实验任务2
源代码 book.hpp,book.cpp,booksale.hpp,booksale.cpp,task2.cpp
点击查看代码 book.hpp
#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
};
点击查看代码 book.cpp
#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;
}
点击查看代码 booksale.hpp
#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
};
点击查看代码 booksale.cpp
#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;
}
点击查看代码 task2.cpp
#include <algorithm>
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>
#include "booksale.hpp"// 按图书销售数量比较
bool compare_by_amount(const BookSale &x1, const BookSale &x2)
{return x1.get_amount() > x2.get_amount();
}void test()
{using std::cin;using std::cout;using std::getline;using std::sort;using std::string;using std::vector;using std::ws;vector<BookSale> sales_records; // 图书销售记录表int books_number;cout << "录入图书数量: ";cin >> books_number;cout << "录入图书销售记录\n";for (int i = 0; i < books_number; ++i){string name, author, translator, isbn;double price;cout << string(20, '-') << "第" << i + 1 << "本图书信息录入" << string(20, '-') << '\n';cout << "录入书名: ";getline(cin >> ws, name);cout << "录入作者: ";getline(cin >> ws, author);cout << "录入译者: ";getline(cin >> ws, translator);cout << "录入isbn: ";getline(cin >> ws, isbn);cout << "录入定价: ";cin >> price;Book book(name, author, translator, isbn, price);double 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_records.push_back(record);}// 按销售册数排序sort(sales_records.begin(), sales_records.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, '=') << '\n';for (auto &record : sales_records){cout << record << '\n';cout << string(40, '-') << '\n';}
}int main()
{test();
}
运行测试截图
-
问题1：重载运算符<<
-
（1）找出运算符
<<被重载了几处？分别用于什么类型？ -
回答：2处，分别用于
Book类、BookSale类。 -
（2）找出使用重载
<<输出对象的代码，写在下面。 -
回答：
Book类重载<<
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;
}
BookSale类重载<<
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;
}
-
问题2：图书销售统计
-
（1）图书销售记录"按销售数量降序排序"，代码是如何实现的？
-
回答：调用
algorithm库的sort函数，以自己实现的compare_by_amount作为排序规则，进行按销售数量降序排序。
// 按图书销售数量比较
bool compare_by_amount(const BookSale &x1, const BookSale &x2)
{return x1.get_amount() > x2.get_amount();
}
// 按销售册数排序sort(sales_records.begin(), sales_records.end(), compare_by_amount);
-
（2）拓展（选答*）：如果使用
lambda表达式，如何实现"按销售数量降序排序"？ -
回答：
// 按销售册数排序sort(sales_records.begin(), sales_records.end(), [](const BookSale &x1, const BookSale &x2){ return x1.get_amount() > x2.get_amount(); });
实验任务3
源代码 task3_1.pp,task3_2.cpp
点击查看代码 task3_1.cpp
#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();
}
点击查看代码 task3_2.cpp
#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();
}
运行测试截图
task3_1.cpp
task3_2.cpp
实验任务4
源代码 Pet.hpp,task4.cpp
点击查看代码 Pet.hpp
#pragma once#include <string>class MachinePet
{
public:MachinePet(const std::string &_nickname) : nickname(_nickname) {}virtual ~MachinePet() = default;std::string get_nickname() const{return nickname;}virtual std::string talk() const = 0;protected:std::string nickname;
};class PetCat : public MachinePet
{
public:PetCat(const std::string &_nickname) : MachinePet(_nickname) {}std::string talk() const override{return "miao wu~";}
};class PetDog : public MachinePet
{
public:PetDog(const std::string &_nickname) : MachinePet(_nickname) {}std::string talk() const override{return "wang wang~";}
};
点击查看代码 task4.cpp
#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const PetCat cat("miku");std::cout << cat.get_nickname() << " says " << cat.talk() << '\n';const 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();
}
运行测试截图
实验任务5
源代码 Complex.hpp,task5.cpp
点击查看代码 Complex.hpp
#pragma oncetemplate <typename T>
class Complex
{
public:Complex(T r = T(), T i = T()) : real(r), imag(i) {}Complex(const Complex<T> &other) : real(other.real), imag(other.imag) {}T get_real() const{return real;}T get_imag() const{return imag;}Complex<T> operator+(const Complex<T> &other) const{return Complex<T>(real + other.real, imag + other.imag);}Complex<T> &operator+=(const Complex<T> &other){real += other.real;imag += other.imag;return *this;}bool operator==(const Complex<T> &other) const{return real == other.real && imag == other.imag;}friend std::ostream &operator<<(std::ostream &os, const Complex<T> &c){os << c.real << (c.imag >= 0 ? " + " : " - ") << std::abs(c.imag) << "i";return os;}friend std::istream &operator>>(std::istream &is, Complex<T> &c){is >> c.real >> c.imag;return is;}private:T real;T imag;
};
点击查看代码 task5.cpp
#include <iostream>
#include "Complex.hpp"void test1()
{using std::boolalpha;using std::cout;Complex<int> c1(2, -5), c2(c1);cout << "c1 = " << c1 << '\n';cout << "c2 = " << c2 << '\n';cout << "c1 + c2 = " << c1 + c2 << '\n';c1 += c2;cout << "c1 = " << c1 << '\n';cout << boolalpha << (c1 == c2) << '\n';
}void test2()
{using std::cin;using std::cout;Complex<double> c1, c2;cout << "Enter c1 and c2: ";cin >> c1 >> c2;cout << "c1 = " << c1 << '\n';cout << "c2 = " << c2 << '\n';const Complex<double> c3(c1);cout << "c3.real = " << c3.get_real() << '\n';cout << "c3.imag = " << c3.get_imag() << '\n';
}int main()
{std::cout << "自定义类模板Complex测试1: \n";test1();std::cout << "\n自定义类模板Complex测试2: \n";test2();
}
运行测试截图
、第五届电子信息工程与计算机通信国际学术会议（EIECC 2025）)
