实验5 继承和多态

实验任务3：

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();
}

pets.cpp：

#include <iostream>
#include <string>

using namespace std;

class MachinePets {
public:
    MachinePets(const string& s):nickname(s){}
    string get_nickname() const{return nickname;}
    virtual string talk() = 0;
protected:
    string nickname;
};

class PetCats : public MachinePets {
public:
    PetCats(const string& s):MachinePets(s){}
    string talk() override{return "miao wu~";}
};

class PetDogs : public MachinePets {
public:
    PetDogs(const string& s):MachinePets(s){}
    string talk() override{return "wang wang~";}
};

运行结果：

 

 实验任务4：

 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();
}

film.hpp：

#pragma once
#include <iostream>
#include <string>
#include <iomanip>

using namespace std;

class Film {
public:
    Film() = default;
    Film(string t, string d, int y, string p) : title(t), director(d), year(y), place(p) {}

    int getYear() const { return year; }

    friend istream& operator>>(istream& is, Film& f)
    {
        cout << "录入片名: "; is >> f.title;
        cout << "录入导演: "; is >> f.director;
        cout << "录入制片国家/地区: "; is >> f.place;
        cout << "录入上映年份: "; is >> f.year;
        return is;
    }

    friend ostream& operator<<(ostream& os, const Film& f)
    {
        os << left << setw(20) << f.title << setw(20) << f.director << setw(20) << f.place << setw(20) << f.year << endl;
        return os;
    }

private:
    string title;
    string director;
    int year;
    string place;
};

bool compare_by_year(const Film& f1, const Film& f2)
{
    if (f1.getYear() < f2.getYear())
        return true;
    return false;
}

运行结果：

 

实验任务5：

 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();
}

Complex.hpp：

#pragma once
#include <iostream>

using namespace std;

template<typename T>
class Complex {
public:
    Complex<T>(T real = 0, T imag = 0) : real(real), imag(imag) {}
    T get_real() const { return real; }
    T get_imag() const { return imag; }

    Complex<T> operator+=(const Complex<T>& a)
    {
        real += a.real;
        imag += a.imag;
        return *this;
    }
    friend Complex<T> operator+(const Complex<T>& a, const Complex<T>& b)
    {
        Complex<T> temp;
        temp.real = a.real + b.real;
        temp.imag = a.imag + b.imag;
        return temp;
    }
    friend bool operator==(const Complex<T>& a, const Complex<T>& b)
    {
        if (a.real == b.real && a.imag == b.imag)
            return true;
        return false;
    }

    friend istream& operator>>(istream& is, Complex<T>& c)
    {
        is >> c.real >> c.imag;
        return is;
    }

    friend ostream& operator<<(ostream& os, const Complex<T>& c)
    {
        if (c.imag >= 0)
            os << c.real << " + " << c.imag << "i";
        else
            os << c.real << " - " << -c.imag << "i";
        return os;
    }

private:
    T real, imag;
};

运行结果：

 

实验任务6：

 8_8.cpp：

#include "account.h"
#include <iostream>
using namespace std;
int main() {
    Date date(2008, 11, 1);        //起始日期
    //建立几个账户
    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*);        //账户总数
    cout << "(d)deposit(w)withdraw(s)show(c)change day(n)next month(e)exit" << endl;
    char cmd;
    do {
        //显示日期和总金额
        date.show();
        cout << "\tTotal: " << Account::getTotal() << "\tcommand>";
        int index, day;
        double amount;
        string desc;
        cin >> cmd;
        switch (cmd) {
        case 'd':    //存入现金
            cin >> index >> amount;
            getline(cin, desc);
            accounts[index]->deposit(date, amount, desc);
            break;
        case 'w':    //取出现金
            cin >> index >> amount;
            getline(cin, desc);
            accounts[index]->withdraw(date, amount, desc);
            break;
        case's':    //查询各账户信息
            for (int i = 0; i < n; i++) {
                cout << "[" << i << "]";
                accounts[i]->show();
                cout << endl;
            }
            break;
        case 'c':    //改变日期
            cin >> day;
            if (day < date.getDay())
                cout << "You cannot specify a previous date";
            else if (day > date.getMaxDay())
                cout << "Invalid day";
            else
                date = Date(date.getYear(), date.getMonth(), day);
            break;
        case 'n':    //进入下一月
            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;
}

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) {     //每年的1月计算一次利息
        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();
}

account.h：

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

class Account {                //账户类
private:
    std::string id;            //账户
    double balance;            //余额
    static double total;    //所有账户的总金额
protected:
    //供派生类调用的构造函数，id为账户
    Account(const Date& date, const std::string& id);
    //记录一笔账，date为日期，amount为金额，desc为说明
    void record(const Date& date, double amount, const std::string& desc);
    //报告错误信息
    void error(const std::string& msg) const;
public:
    const std::string& getId() const { return id; }
    double getBalance() const { return balance; }
    static double getTotal() { return total; }
    //存入现金，date为日期，amount为金额，desc为款项说明
    virtual void deposit(const Date& date, double amount, const std::string& desc) = 0;
    //取出现金，date为日期，amount为金额，desc为款项说明
    virtual void withdraw(const Date& date, double amount, const std::string& desc) = 0;
    //结算（计算利息、年费等），每月结算一次，date为结算日期
    virtual void settle(const Date& date) = 0;
    //显示账户信息
    virtual void show() const;
};
class SavingsAccount :public Account {
private:
    Accumulator acc;
    double rate;
public:
    SavingsAccount(const Date& date, const std::string& id, double rate);
    double getRate()const { return rate; }

    void deposit(const Date& date, double amount, const std::string& desc);
    void withdraw(const Date& date, double amount, const std::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 std::string& id, double credit, double rate, double fee);
    double getCredit()const { return credit; }
    double getRate()const { return rate; }
    double getAvailableCredit()const {
        if (getBalance() < 0)
            return credit + getBalance();
        else
            return credit;
    }
    void deposit(const Date& date, double amount, const std::string& desc);
    void withdraw(const Date& date, double amount, const std::string& desc);
    void settle(const Date& date);
    void show()const;
};
#endif //__ACCOUNT_H__

accumulator.h：

#ifndef __ACCUMULATOR_H__
#define __ACCUMULATOR_H__
#include "date.h"
class Accumulator {        //将某个数值按日累加
private:
    Date lastDate;        //上次变更数值的日期
    double value;        //数值的当前值
    double sum;            //数值按日累加之和
public:
    //构造函数，date为开始累加的日期，value为初始值
    Accumulator(const Date& date, double value) : lastDate(date), value(value), sum(0) {}
    //获得到日期date的累加结果
    double getSum(const Date& date) const {
        return sum + value * (date - lastDate);
    }
    //在date将数值变更为value
    void change(const Date& date, double value) {
        sum = getSum(date);
        lastDate = date;
        this->value = value;
    }
    //初始化，将日期变为date，数值变为value，累加器清零
    void reset(const Date& date, double value) {
        lastDate = date;
        this->value = value;
        sum = 0;
    }
};
#endif //__ACCUMULATOR_H__

date.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();
}

date.h：

//date.h
#ifndef __DATE_H__
#define __DATE_H__
class Date {    //日期类
private:
    int year;        //年
    int month;        //月
    int day;        //日
    int totalDays;    //该日期是从公元元年1月1日开始的第几天
public:
    Date(int year, int month, int day);        //用年、月、日构造日期
    int getYear() const { return year; }
    int getMonth() const { return month; }
    int getDay() const { return day; }
    int getMaxDay() const;        //获取当月有多少天
    bool isLeapYear() const {        //判断当年是否为闰年
        return (year % 4 == 0 && year % 100 != 0) || year % 400 == 0;
    }
    void show() const;        //输出当前日期
    int operator-(const Date& date) const {        //计算两个日期之间差多少天
        return totalDays - date.totalDays;
    }
};
#endif    //__DATE_H__

运行结果：