实验五继承和多态

标签：const string 继承 double 多态 Date 实验 date include

实验任务三

#include <iostream>
#include <string>
#pragma once
using namespace std;

class MachinePets {
private:
    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() override {
        return "miao wu~"; 
    }
};

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

pet.hpp

#include <iostream>
#include "pet.hpp"
void play(MachinePets &obj) {
          std::cout << obj.get_nickname() 
          << " says " << obj.talk() << std::endl;
}
 
void test() {
PetCats cat("miku");
PetDogs dog("da huang");
play(cat);
play(dog);
}
int main() {
test();}

pet.cpp

实验任务四

#include <iostream>
#include <string>
#include <vector>
#include <limits>
#pragma once 

using namespace std;

class Person {
private:
    string name;
    string telephone;
    string email;

public:
    Person(const string& n, const string& t, const string& e = "")
        : name{n}, telephone{t}, email{e} {}
    Person() : name(""), telephone(""), email("") {}
    Person(const Person& other) : name{other.name}, telephone{other.telephone}, email{other.email} {}

void update_telephone() {
    cin.clear();
    cout << "输入电话号码：";
    telephone.clear();
    string Newtelephone;
    getline(cin, Newtelephone);
    this->telephone=Newtelephone;
    cout << "电话号码已更新..." << endl;
}

void update_email() {
    cout << "输入email地址：";
 
    email.clear();
    string Newemail ;
    getline(cin, Newemail);
    this->email=Newemail; 
}


    friend ostream& operator<<(ostream& os, const Person& person) {
        os << "Name: " << person.name << "\nTelephone: " << person.telephone << "\nEmail: " << person.email<<endl;
        return os;
    }

    friend istream& operator>>(istream& is, Person& person) {
        getline(is, person.name);
        getline(is, person.telephone);
        getline(is, person.email);
        
        cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
        return is;
    }

    friend bool operator==(const Person& P1, const Person& P2) {
        return (P1.name == P2.name) && (P1.telephone == P2.telephone);
    }
};

person.hpp

#include<iostream>
#include <iostream>
#include <string>
#include <vector>
#include <limits>
#include"person.hpp"
using namespace std;

void test() {
    vector<Person> phone_book;
    Person p;
    cout << "输入一组联系人的联系方式，直至按下Ctrl+Z终止\n";
    while (cin >> p) {
        phone_book.push_back(p);
    }
    
 

    cout << "\n更新phone_book中索引为0的联系人的手机号、邮箱:\n";
    phone_book.at(0).update_telephone();
    phone_book.at(0).update_email();
  

    cout << "\n测试两个联系人是否是同一个:\n";
    if (phone_book.size() > 1) {
        cout<<phone_book[0]<<phone_book[1];
        cout << boolalpha << (phone_book.at(0) == phone_book.at(1)) << endl;
    }
}

int main() {
    test();
    return 0;
}

person.cpp

这里加上了输出成员数据状况，让程序更加清晰，且可以发现有没有正确更新，是否清除缓冲区。

实验任务五

#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');
}

8_8.cpp

#pragma once
#include<iostream>
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;
    }
};

date.h

#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.cpp

#pragma once
#include"accumulator.h"
#include"date.h"
#include<iostream>
#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() const { 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;
};

account.h

accumulator.h

#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();
}

account.h

实验感悟

当我们使用cin进行用户输入时，输入的字符会被存储在输入缓冲区中，直到按下 Enter 键。如果不适时清除输入缓冲区，可能会导致下一次输入时，程序直接读取到缓冲区中尚未被处理的残留字符，从而产生错误的行为。
当使用 getline 函数读取一整行字符串时，如果之前使用过 cin等输入函数，需要在调用getline之前清除输入缓冲区，否则可能会导致getline 直接读取到之前输入的换行符，而不等待用户输入。
常见的清除输入缓冲区的方法包括使用cin.ignore() 函数可以清除缓冲区中的一个字符，而cin.sync()可以清除缓冲区中的所有字符。
实验五 Date 类来表示日期，SavingsAccount 类和 CreditAccount 类分别继承自 Account 类。
SavingsAccount 和 CreditAccount 类分别实现了储蓄账户和信用卡账户的具体逻辑，包括计算利息、存款、取款等功能。
Account 类是一个抽象基类，包含了虚函数，通过使用基类指针数组存储不同类型的账户，实现了多态性，可以通过基类指针统一调用不同派生类的函数。

标签：const,string,继承,double,多态,Date,实验,date,include
From： https://www.cnblogs.com/xiaochengxiatian/p/17873835.html

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实验五 继承和多态

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