实验5
实验任务1：
源代码：
点击查看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();
}
问题1：
（1）纯虚函数，virtual void publish() const = 0。
（2）不能，因为Publisher是抽象类。
问题2：
（1）纯虚函数，void publish() const override和void use() const override。
（2）如图：
问题3
（1）基类指针。
（2）Book、Film、Music。
（3）为了实现 “析构多态”避免内存泄漏，派生类的成员无法被正确释放，导致内存泄漏。
实验任务2
源代码
点击查看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booksale.hpp
#pragma once
#include <string>
#include "book.hpp"
// 图书销售记录类BookSale: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; // 图书信息
double sales_price; // 售价
int sales_amount; // 销售数量
};
点击查看booksale.cpp
#include <<iomanip>
#include <iostream>
#include <string>
#include "booksale.hpp"
// 图书销售记录类BookSale: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task2.cpp
#include "booksale.hpp"
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
// 按图书销售数额比较（降序）
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);
}
// 按销售册数降序排序
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();
}
问题1
（1） 被重载了 2 处，分别用于Book类和BookSale类。
（2）cout << item.rb << '\n'和cout << t << endl。
问题2
（1）先定义比较函数compare_by_amount，返回x1.get_amount() > x2.get_amount()，实现销售数量降序逻辑。调用标准库sort函数，传入容器首尾迭代器sales_lst.begin()和sales_lst.end()，并指定比较函数compare_by_amount，完成排序。
实验任务3
略
实验任务4
补全代码
点击查看pet.hpp
#pragma once
#include <string>
// 机器宠物抽象类（MachinePet）
class MachinePet {
public:
// 构造函数：用字符串初始化昵称
MachinePet(const std::string& nickname_) : nickname(nickname_) {}
// 虚析构函数：确保派生类对象正确析构
virtual ~MachinePet() = default;
// 接口：获取昵称
std::string get_nickname() const {
return nickname;
}
// 纯虚函数：叫声接口（运行时多态，派生类实现）
virtual std::string talk() const = 0;
protected:
std::string nickname; // 机器宠物昵称
};
// 电子宠物猫类（PetCat）：公有继承自MachinePet
class PetCat : public MachinePet {
public:
// 构造函数：初始化昵称（通过初始化列表传递给基类）
PetCat(const std::string& nickname_) : MachinePet(nickname_) {}
// 实现talk()：返回猫叫声
std::string talk() const override {
return "miao wu~";
}
};
// 电子宠物狗类（PetDog）：公有继承自MachinePet
class PetDog : public MachinePet {
public:
// 构造函数：初始化昵称（通过初始化列表传递给基类）
PetDog(const std::string& nickname_) : MachinePet(nickname_) {}
// 实现talk()：返回狗叫声
std::string talk() const override {
return "wang wang~";
}
};
点击查看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();
}
实验任务5
完整代码
点击查看Complex.hpp
#pragma once
#include <iostream>
// 复数类模板Complex
template<typename T>
class Complex {
public:
// 1. 构造函数（支持默认构造、带参构造、拷贝构造）
Complex() : real(0), imag(0) {} // 默认构造：实部虚部均为0
Complex(T r, T i) : real(r), imag(i) {} // 带参构造：初始化实部和虚部
Complex(const Complex<T>& other) : real(other.real), imag(other.imag) {} // 拷贝构造
// 2. 接口：获取实部和虚部
T get_real() const { return real; }
T get_imag() const { return imag; }
// 3. 运算符重载：+=（成员函数，支持复数相加）
Complex<T>& operator+=(const Complex<T>& rhs) {
this->real += rhs.real;
this->imag += rhs.imag;
return *this;
}
// 4. 运算符重载：==（成员函数，判断复数相等）
bool operator==(const Complex<T>& rhs) const {
return (this->real == rhs.real) && (this->imag == rhs.imag);
}
// 5. 友元函数：重载<<（输出复数，格式：实部±虚部i）
friend std::ostream& operator<<(std::ostream& out, const Complex<T>& c) {
out << c.real;
if (c.imag >= 0) {
out << "+" << c.imag << "i";
} else {
out << c.imag << "i"; // 虚部为负时，直接输出负号
}
return out;
}
// 6. 友元函数：重载>>（输入复数，支持两种输入格式：a b 或 a±bi）
friend std::istream& operator>>(std::istream& in, Complex<T>& c) {
in >> c.real >> c.imag;
return in;
}
private:
T real; // 复数实部
T imag; // 复数虚部
};
// 7. 运算符重载：+（非成员函数，支持复数+复数）
template<typename T>
Complex<T> operator+(const Complex<T>& lhs, const Complex<T>& rhs) {
return Complex<T>(lhs.get_real() + rhs.get_real(), lhs.get_imag() + rhs.get_imag());
}
点击查看task5.cpp
#include <iostream>
#include "Complex.hpp"
void test1() {
using std::cout;
using std::boolalpha;
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();
}
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