实验五

任务三：

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

#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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 任务4：

运行截图：

 

#pragma once
#include<iostream>
#include<string>
using namespace std;
class Film{
    public:
        Film(){}
        friend istream& operator>>(istream& in, Film& film){
            cout <<"录入片名:" ;          in>>film.name;
            cout <<"录入导演:" ;          in>>film.director;
            cout <<"录入制片国家、地区:" ;in>> film.country;
            cout <<"录入上映年份:";       in>> film.time;
            return in; 
        }
        friend ostream& operator<<(ostream& out,const Film& film){
            out<<left;
            out<<setw(8)<<film.name<<setw(10)<<film.director<<setw(8)<<film.country<<film.time;
            return out;
        }
        int get_time()const{return time;}
    private:
        string name;//片名
        string director;//导演
        string country;//国家
        int time;//上映时间 
}; 

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

任务5：

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

#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();
}

任务六：

 

#pragma once

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;
        }
};

#include "date.h"
#include <iostream>
#include <cstdlib>

using namespace std;

namespace {
    const int DAYS_BEFIRE_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_BEFIRE_MONTH[month - 1] + day;
    if (isLeapYear() && month > 2) totalDays++;
}

int Date::getMaxDay() const {
    if (isLeapYear() && month == 2)
        return 29;
    else
        return DAYS_BEFIRE_MONTH[month] - DAYS_BEFIRE_MONTH[month - 1];
}

void Date::show() const {
    cout << getYear() << "-" << getMonth() << "-" << getDay();
}

#pragma once

#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).getTotalDays(); // 假设Date类有getTotalDays()方法来计算日期差
    }

    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; // 修复了原始代码中的错误，这里应该赋值
        sum = 0;
    }
};

#pragma once

#include "date.h"
#include "accumulator.h"
#include <string>

using namespace std;

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

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;
};

#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) {
    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();
}

#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;
}

运行截图：

 将公共操作声明为虚函数，是程序的多态性更加显露。通过基类指针来执行各种操作，极其简便，我们可以通过公共操作来改变各个账户。