实验5.继承和多态

1.实验任务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();
}

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2.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();
}

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3.实验任务3：

pets.hpp:

#pragma once
#include <iostream>
using namespace std;
class MachinePets {
public:
    MachinePets(const string&s=""):nickname{s}{ }
public:
    virtual string get_nickname() const = 0;
    virtual string talk()const = 0;
protected:
    string nickname;
};
class PetCats:public MachinePets {
public:
    PetCats(const string &s=""):MachinePets{s}{ }
public:
    string get_nickname()const override {
        return nickname;
    }
    string talk()const override {
        return talking;
    }
private:
    string talking = "miao wu~";
};
class PetDogs :public MachinePets {
public:
    PetDogs(const string& s = "") :MachinePets{ s } { }
public:
    string get_nickname()const override {
        return nickname;
    }
    string talk()const override {
        return talking;
    }
private:
    string talking = "wang wang~";
};

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();
}

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4.实验任务4：

film.hpp:

#pragma once
#include <iostream>
#include <string>
using namespace std;
class Film {
public:
    friend istream& operator>>(istream& in,  Film& f);
    friend ostream& operator<<(ostream& out, const Film& f);
    Film(){ }
    int get_age() const { return age; }
private:
    string name;
    string director;
    string nation;
    int age;
};
istream& operator>>(istream& in,  Film& f) {
    cout << "录入片名：";
    in >> f.name;
    cout << "录入导演：";
    in >> f.director;
    cout << "录入制片国家/地区：";
    in >> f.nation;
    cout << "录入上映年份：";
    in >> f.age;
    return in;
}
ostream& operator<<(ostream& out, const Film& f) {
    out << f.name << string(5, ' ') << f.director << string(5, ' ') << f.nation << string(5, ' ') << f.age;
    return out;
}

task4.cpp:

#include "film.hpp"
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
bool compare_by_year(const Film& x, const Film& y) { return x.get_age() < y.get_age(); }
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();
}

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5.实验任务5：

Complex.hpp:

#pragma once
#include <iostream>
#include <string>
using namespace std;
template <typename T>
class Complex {
public:
    Complex(T real = 0, T imag = 0) :real{ real }, imag{ imag } { }
    Complex(const Complex<T>& c) {
        this->real = c.real;
        this->imag = c.imag;
    }
    T get_real() const { return real; }
    T get_imag()const { return imag; }
    Complex operator+=(const Complex<T>& c) {
        this->real +=c.real;
        this->imag += c.imag;
        return *this;
    }
public:
    friend Complex<T> operator+(const Complex<T>& c1, const Complex<T>& c2) {
        return Complex<T>(c1.real + c2.real, c1.imag + c2.imag);
    }
    bool operator==(const Complex<T>& c)const {
        return real == c.real && imag == c.imag;
    }
    friend ostream& operator<<(ostream& out, const Complex<T>& c) {
        if (c.get_imag() < 0)
            out << c.get_real() << " - " << -c.get_imag() << "i";  
        else
            out << c.get_real() << " + " << c.get_imag() << "i";

        return out;
    }
    friend istream& operator>>(istream& in, Complex<T>& c) {
        in >> c.real >> c.imag;
        return in;
    }
private:
    T real;
    T imag;
};

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();
}

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6.实验任务6：

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.cpp:

#include "date.h"
#include <iostream>
#include <cstdlib>
using namespace std;

//命名空间使下面的定义只在当前文件中有效
namespace {
    //存储平年中的某个月1日之前有多少天，为便于getMaxDay函数的实现，该数组多出一项
    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();
}

accumulator.h:

#ifndef __ACCUMULATOR_H__
#define __ACCUMULATOR_H__
#include "date.h"
class Accumulator {
private:
    Date lastDate;
    double value;
    double sum;
public:
    Accumulator(const Date& date, double value) : lastDate(date), value(value), sum{ 0 } { }
    double getSum(const Date& date) const {
        return sum + value * (date - lastDate);
    }
    void change(const Date& date, double value) {
        sum = getSum(date);
        lastDate = date;
        this->value = value;
    }
    void reset(const Date& date, double value) {
        lastDate = date;
        this->value = value;
        sum = 0;
    }
};
#endif

account.h:

#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
#include "date.h"
#include "accumulator.h"
#include <string>

class Account {
private:
    std::string id;
    double balance;
    static double total;
protected:
    Account(const Date& date, const std::string& id);
    void record(const Date& date, double amount, const std::string& desc);
    void error(const std::string& msg) const;
public:
    const std::string& getId() { return id; }
    double getBalance() const { return balance; }
    static double getTotal() { return total; }
    virtual void deposit(const Date& date, double amount, const std::string& desc) = 0;
    virtual void withdraw(const Date& date, double amount, const std::string& desc) = 0;
    virtual void settle(const Date& date) = 0;
    virtual void show() const;
};
using namespace std;
class SavingsAccount : public Account {
private:
    Accumulator acc;
    double rate;
public:
    SavingsAccount(const Date& date, const string& id, double rate);
    double getRate() const { return rate; }
    void deposit(const Date& date, double amount, const string& desc);
    void withdraw(const Date& date, double amount, const string& desc);
    void settle(const Date& date);
};

class CreditAccount : public Account {
private:
    Accumulator acc;
    double credit;
    double rate;
    double fee;
    double getDebt() const {
        double balance = getBalance();
        return (balance < 0 ? balance : 0);
    }
public:
    CreditAccount(const Date& date, const string& id, double credit, double rate, double fee);
    double getCredit() const { return credit; }
    double getRate() const { return rate; }
    double getFee() const { return fee; }
    double getAvailableCredit() const {
        if (getBalance() < 0) return credit + getBalance();
        else return credit;
    }
    void deposit(const Date& date, double amount, const string& desc);
    void withdraw(const Date& date, double amount, const string& desc);
    void settle(const Date& date);
    void show() const;
};
#endif

account.cpp:

#include "account.h"
#include <cmath>
#include<iostream>
using namespace std;

double Account::total = 0;

Account::Account(const Date& date, const string& id) : id(id), balance(0) {
    date.show();
    cout << "\t#" << id << " created" << endl;
}

void Account::record(const Date& date, double amount, const string& desc) {
    amount = floor(amount * 100 + 0.5) / 100;
    balance += amount;
    total += amount;
    date.show();
    cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;
}

void Account::show() const {
    cout << id << "\tBalance: " << balance;
}

void Account::error(const string& msg) const {
    cout << "Error (#" << id << "): " << msg << endl;
}

SavingsAccount::SavingsAccount(const Date& date, const string& id, double rate)
    : Account(date, id), rate(rate), acc(date, 0) {}

void SavingsAccount::deposit(const Date& date, double amount, const string& desc) {
    record(date, amount, desc);
    acc.change(date, getBalance());
}

void SavingsAccount::withdraw(const Date& date, double amount, const string& desc) {
    if (amount > getBalance()) {
        error("not enough money");
    }
    else {
        record(date, -amount, desc);
        acc.change(date, getBalance());
    }
}

void SavingsAccount::settle(const Date& date) {
    if (date.getMonth() == 1) {
        double interest = acc.getSum(date) * rate / (date - Date(date.getYear() - 1, 1, 1));
        if (interest != 0) record(date, interest, "interest");
        acc.reset(date, getBalance());
    }
}

CreditAccount::CreditAccount(const Date& date, const string& id, double credit, double rate, double fee)
    : Account(date, id), credit(credit), rate(rate), fee(fee), acc(date, 0) {}

void CreditAccount::deposit(const Date& date, double amount, const string& desc) {
    record(date, amount, desc);
    acc.change(date, getDebt());
}

void CreditAccount::withdraw(const Date& date, double amount, const string& desc) {
    if (amount - getBalance() > credit) {
        error("not enough credit");
    }
    else {
        record(date, -amount, desc);
        acc.change(date, getDebt());
    }
}

void CreditAccount::settle(const Date& date) {
    double interest = acc.getSum(date) * rate;
    if (interest != 0) record(date, interest, "interest");
    if (date.getMonth() == 1) record(date, -fee, "annual fee");
    acc.reset(date, getDebt());
}

void CreditAccount::show() const {
    Account::show();
    cout << "\tAvailable credit: " << getAvailableCredit();
}

8_8.cpp:

#include "account.h"
#include<iostream>
using namespace std;
int main() {
    Date date(2008, 11, 1);
    SavingsAccount sa1(date, "S3755217", 0.015);
    SavingsAccount sa2(date, "02342342", 0.015);
    CreditAccount ca(date, "C5392394", 10000, 0.0005, 50);
    Account* accounts[] = { &sa1, &sa2, &ca };
    const int n = sizeof(accounts) / sizeof(Account*);
    cout << "(d)deposit (w)withdraw (s)show (c)change day (n)next month (e)exit" << endl;
    char cmd;
    do {
        date.show();
        cout << "\tTotal:" << Account::getTotal() << "\tcommand>";
        int index, day;
        double amount;
        string desc;
        cin >> cmd;
        switch (cmd) {
        case 'd':
            cin >> index >> amount;
            getline(cin, desc);
            accounts[index]->deposit(date, amount, desc);
            break;
        case 'w':
            cin >> index >> amount;
            getline(cin, desc);
            accounts[index]->withdraw(date, amount, desc);
            break;
        case 's':
            for (int i = 0; i < n; i++) {
                cout << "[" << i << "]";
                accounts[i]->show();
                cout << endl;
            }
            break;
        case 'c':
            cin >> day;
            if (day < date.getDay()) {
                cout << "You cannot specify a previous day";
            }
            else if (day > date.getMaxDay())
                cout << "Invalid day";
            else date = Date(date.getYear(), date.getMonth(), day);
            break;
        case 'n':
            if (date.getMonth() == 12)
                date = Date(date.getYear() + 1, 1, 1);
            else date = Date(date.getYear(), date.getMonth() + 1, 1);
            for (int i = 0; i < n; i++) {
                accounts[i]->settle(date);
            }
            break;
        }
    } while (cmd != 'e');
    return 0;
}

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