一.实验目的
正确使用C++语法定义和使用派生类
1. 正确使用C++语法重载运算符，理解编译器是如何将表达式转换为对运算符重载函数的调用的
2. 基于问题场景，合理使用派生机制、虚函数、纯虚函数、抽象类，实现接口继承与运行时多态
3. 能灵活应用类的组合、继承、多态编程解决实际问题
二.实验内容
实验1
publisher.hpp
#pragma once
#include <iostream>
#include <string>
using std::cout;
using std::endl;
using std::string;
// 发行/出版物类：Publisher （抽象类）
class Publisher {
public:
Publisher(const string &s = ""); // 构造函数
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:
string name; // 发行/出版物名称
};
Publisher::Publisher(const string &s): name {s} {
}
// 图书类: Book
class Book: public Publisher {
public:
Book(const string &s = "", const string &a = ""); // 构造函数
public:
void publish() const override; // 接口
void use() const override; // 接口
private:
string author; // 作者
};
Book::Book(const string &s, const string &a): Publisher{s}, author{a} {
}
void Book::publish() const {
cout << "Publishing book: 《" << name << "》 by " << author << endl;
}
void Book::use() const {
cout << "Reading book: " << name << " by " << author << endl;
}
// 电影类: Film
class Film: public Publisher {
public:
Film(const string &s = "", const string &d = ""); // 构造函数
public:
void publish() const override; // 接口
void use() const override; // 接口
private:
string director; // 导演
};
Film::Film(const string &s, const string &d): Publisher{s}, director{d} {
}
void Film::publish() const {
cout << "Publishing film: <" << name << "> directed by " << director << endl;
}
void Film::use() const {
cout << "Watching film: " << name << " directed by " << director << endl;
}
// 音乐类：Music
class Music: public Publisher {
public:
Music(const string &s = "", const string &a = "");
public:
void publish() const override; // 接口
void use() const override; // 接口
private:
string artist; // 音乐艺术家名称
};
Music::Music(const string &s, const string &a): Publisher{s}, artist{a} {
}
void Music::publish() const {
cout << "Publishing music <" << name << "> by " << artist << endl;
}
void Music::use() const {
cout << "Listening to music: " << name << " by " << artist << endl;
}
task1.cpp
#include "publisher.hpp"
#include <vector>
#include <typeinfo>
using std::vector;
void test() {
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(auto &ptr: v) {
cout << "pointer type: " << typeid(ptr).name() << endl; // 输出指针类型
cout << "RTTI type: " << typeid(*ptr).name() << endl; // 输出指针指向的对象类型
ptr->publish();
ptr->use();
cout << endl;
}
}
int main() {
test();
}
运行结果
实验任务2
book.hpp
#pragma once
#include <string>
#include <iostream>
#include <iomanip>
using std::string;
using std::ostream;
using std::endl;
using std::setw;
using std::left;
class Book {
public:
Book(const string &name, const string &author, const string &translator, const string &isbn, float price);
friend ostream& operator<<(ostream &out, const Book &book);
private:
string name; // 书名
string author; // 作者
string translator; // 译者
string isbn; // isbn号
float price; // 定价
};
// 成员函数实现
Book::Book(const string &name, const string &author, const string &translator, const string &isbn, float price) {
this->name = name;
this->author = author;
this->translator = translator;
this->isbn = isbn;
this->price = price;
}
// 友元实现
ostream& operator<<(ostream &out, const Book &book) {
out << left;
out << setw(15) << "书名:" << book.name << endl
<< setw(15) << "作者:" << book.author << endl
<< setw(15) << "译者:" << book.translator << endl
<< setw(15) << "ISBN:" << book.isbn << endl
<< setw(15) << "定价:" << book.price;
return out;
}
booksale.hpp
#pragma once
#include "book.hpp"
#include <iostream>
#include <string>
#include <iomanip>
using std::string;
using std::cout;
using std::endl;
using std::setw;
class BookSale {
public:
BookSale(const Book &b, float price, int amount);
int get_amount() const;
friend ostream& operator<<(ostream &out, const BookSale &item);
private:
Book rb;
float sales_price; // 售价
int sales_amount; // 销售数量
float revenue; // 营收
};
// 成员函数实现
BookSale::BookSale(const Book &b, float price, int amount): rb{b}, sales_price(price), sales_amount{amount} {
revenue = sales_amount * sales_price;
}
int BookSale::get_amount() const {
return sales_amount;
}
// 友元函数实现
ostream& operator<<(ostream &out, const BookSale &item) {
out << left;
out << item.rb << endl
<< setw(15) << "售价:" << item.sales_price << endl
<< setw(15) << "销售数量:" << item.sales_amount << endl
<< setw(15) << "营收:" << item.revenue;
return out;
}
task2.cpp
#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();
}
实验结果
实验任务3
pets.hpp
#include <string>
#include <iostream>
using namespace std;
class MachinePets {
public:
virtual ~MachinePets() = default;
virtual string get_nickname() const = 0;
virtual string talk() const = 0;
};
class PetCats : public MachinePets {
private:
string nickname;
public:
PetCats(const string& name) : nickname(name) {}
string get_nickname() const override {
return nickname;
}
string talk() const override {
return "Meow";
}
};
class PetDogs : public MachinePets {
private:
string nickname;
public:
PetDogs(const string& name) : nickname(name) {}
string get_nickname() const override {
return nickname;
}
string talk() const override {
return "Woof";
}
};
task3.cpp
#include <iostream>
#include <vector>
#include "pets.hpp"
void test() {
using namespace std;
vector<MachinePets *> pets;
pets.push_back(new PetCats("miku"));
pets.push_back(new PetDogs("da huang"));
for(auto &ptr: pets)
cout <<ptr->get_nickname() << " says " << ptr->talk() << endl;
}
int main() {
test();
}
运行结果
实验任务4
film.hpp
#include <iostream>
#include <string>
using namespace std;
class Film{
private:
string title;
int year;
public:
Film(string t="", int y=0):title(t), year(y){}
int getYear() const { return year; }
friend istream& operator>>(istream& in, Film& film) {
cout << "请输入电影标题: ";
in >> std::ws;
getline(in, film.title);
cout << "请输入发行年份: ";
in >> film.year;
return in;
}
friend ostream& operator<<(ostream& out, const Film& film) {
out << "电影标题: " << film.title <<
", 发行年份: " << film.year ;
return out;
}
};
bool compare_by_year(const Film& f1, const Film& f2) {
return f1.getYear() < f2.getYear();
}
task4.cpp
#include "film.hpp"
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
void test() {
using namespace std;
int n;
cout << "输入电影数目: ";
cin >> n;
cout << "录入" << n << "部影片信息" << endl;
vector<Film> film_lst;
for(int i = 0; i < n; ++i) {
Film f;
cout << string(20, '-') << "第" << i+1 << "部影片录入" << string(20, '-') << endl;
cin >> f;
film_lst.push_back(f);
}
// 按发行年份升序排序
sort(film_lst.begin(), film_lst.end(), compare_by_year);
cout << string(20, '=') + "电影信息(按发行年份)" + string(20, '=')<< endl;
for(auto &f: film_lst)
cout << f << endl;
}
int main() {
test();
}
运行结果
实验任务5
complex.hpp
#include <iostream>
#include <string>
using namespace std;
template <typename T>
class Complex {
private:
T real;
T imag;
public:
Complex(double r = 0, double i = 0): real(r), imag(i) {}
T get_real () const { return real; }
T get_imag () const { return imag; }
Complex operator+(const Complex& other) const {
return Complex(real + other.real, imag + other.imag);
}
Complex& operator+=(const Complex& other) {
real += other.real;
imag += other.imag;
return *this;
}
bool operator==(const Complex& other) const {
return real == other.real && imag == other.imag;
}
friend istream& operator>>(istream& in, Complex& c) {
in >> c.real >> c.imag;
return in;
}
friend ostream& operator<<(ostream& out, const Complex& c) {
out << "(" << c.real << " + " << c.imag << "i)";
return out;
}
};
task5.cpp
#include "Complex.hpp"
#include <iostream>
using std::cin;
using std::cout;
using std::endl;
using std::boolalpha;
void test1() {
Complex<int> c1(2, -5), c2(c1);
cout << "c1 = " << c1 << endl;
cout << "c2 = " << c2 << endl;
cout << "c1 + c2 = " << c1 + c2 << endl;
c1 += c2;
cout << "c1 = " << c1 << endl;
cout << boolalpha << (c1 == c2) << endl;
}
void test2() {
Complex<double> c1, c2;
cout << "Enter c1 and c2: ";
cin >> c1 >> c2;
cout << "c1 = " << c1 << endl;
cout << "c2 = " << c2 << endl;
cout << "c1.real = " << c1.get_real() << endl;
cout << "c1.imag = " << c1.get_imag() << endl;
}
int main() {
cout << "自定义类模板Complex测试1: " << endl;
test1();
cout << endl;
cout << "自定义类模板Complex测试2: " << endl;
test2();
}
运行结果
实验任务6
date.hpp
//date.h
#ifndef DATE_H
#define DATE_H
class Date {
private:
int year;
int month;
int day;
int totalDays;
public:
Date(int year, int month, int day);
int getYear()const { return year; }
int getMonth()const { return month; }
int getDay()const { return day; }
int getMaxDay()const;
bool isLeapYear()const {
return (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0));
}
void show()const;
int operator-(const Date& date)const {
return totalDays - date.totalDays;
}
};
#endif // DATE_H
task6.cpp
#include"date.h"
#include<iostream>
#include<cstdlib>
using namespace std;
namespace {
const int DAYS_BEFORE_MONTH[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
}
Date::Date(int year, int month, int day) :year(year), month(month), day(day) {
if (day <= 0 || day > getMaxDay()) {
cout << "Invalid date!";
show();
cout << endl;
exit(1);
}
int years = year - 1;
totalDays = years * 365 + years / 4 - years / 100 + years / 400 + DAYS_BEFORE_MONTH[month - 1] + day;
if (isLeapYear() && month > 2)
totalDays++;
}
int Date::getMaxDay() const {
if (isLeapYear() && month == 2)
return 29;
else
return DAYS_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];
}
void Date::show() const {
cout << getYear() << "-" << getMonth() << "-" << getDay();
}
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