实验2 类与对象

 

3.实验任务3

#pragma once

#include <iostream>
#include <cmath>

class Complex {
public:
    Complex(double r = 0, double i = 0) : real(r), imag(i) {}

    double get_real() const {
        return real;
    }

    double get_imag() const {
        return imag;
    }

    void add(const Complex &c) {
        real += c.get_real();
        imag += c.get_imag();
    }

    void show() const {
        std::cout << real;
        if (imag > 0) {
            std::cout << " + " << abs(imag) << "i";
        }
        else if (imag < 0) {
            std::cout << " - " << abs(imag) << "i";
        }
    }

    friend Complex add(const Complex &c1, const Complex &c2);
    friend bool is_equal(const Complex &c1, const Complex &c2);
    friend double abs(const Complex &c);

private:
    double real;
    double imag;
};

Complex add(const Complex &c1, const Complex &c2) {
    return Complex(c1.get_real() + c2.get_real(), c1.get_imag() + c2.get_imag());
}

bool is_equal(const Complex &c1, const Complex &c2) {
    return c1.get_real() == c2.get_real() && c1.get_imag() == c2.get_imag();
}

double abs(const Complex &c) {
    return sqrt(pow(c.get_real(), 2) + pow(c.get_imag(), 2));
}

#include "complex.hpp"

// 复数类Complex: 测试
void test() {
    using namespace std;

    Complex c1(3, -4);
    const Complex c2(4.5);
    Complex c3(c1);

    cout << "c1 = ";
    c1.show();
    cout << endl;

    cout << "c2 = ";
    c2.show();
    cout << endl;
    cout << "c2.imag = " << c2.get_imag() << endl;

    cout << "c3 = ";
    c3.show();
    cout << endl;

    cout << "abs(c1) = ";
    cout << abs(c1) << endl;

    cout << boolalpha;
    cout << "c1 == c3 : " << is_equal(c1, c3) << endl;
    cout << "c1 == c2 : " << is_equal(c1, c2) << endl;

    Complex c4;
    c4 = add(c1, c2);
    cout << "c4 = c1 + c2 = ";
    c4.show();
    cout <<endl;

    c1.add(c2);
    cout << " c1 += c2, " << " c1 = ";
    c1.show();
    cout << endl;
}

int main(){
    test();
}

 

4.实验任务4

#ifndef USER_H
#define USER_H

#include <iostream>
#include <string>
#include <vector>

class User {
private:
    std::string name;
    std::string password;
    std::string email;
    static int n;

public:
    static void print_n();

    User(std::string x, std::string y = "111111", std::string z = "      ")
        : name(x), password(y), email(z) {
        ++n;
    }

    ~User() {
        --n;
    }

    void set_email() {
        std::string a;
        std::cout << "Enter email address: ";
        std::cin >> a;
        email = a;
        std::cout << "Email is set successfully..." << std::endl;
    }

    void change_password() {
        int count = 0;
        std::string b, c;
        std::cout << "Enter old password: ";
        std::cin >> b;
        while (b != password) {
            count++;
            std::cout << "Password input error. Please re-enter it: ";
            std::cin >> b;
            if (count >= 2) {
                std::cout << "Password input error. Please try again after a while." << std::endl;
                break;
            }
        }
        if (b == password) {
            std::cout << "Enter new password: ";
            std::cin >> c;
            password = c;
            std::cout << "New password is set successfully..." << std::endl;
        }
    }

    void print_info() {
        std::string masked_password(password.size(), '*');
        std::cout << "Name: " << name << std::endl;
        std::cout << "Password: " << masked_password << std::endl;
        std::cout << "Email: " << email << std::endl;
    }
};

int User::n = 0;

void User::print_n() {
    std::cout << "There are " << n << " users" << std::endl;
}

#endif

#include "User.hpp"
#include <iostream>


void test(){
      using std::cout;
      using std::endl;

      cout << "testing 1......\n";
      User user1("Jonny", "92197", "xyz@hotmail.com");
      user1.print_info();

      cout << endl
           << "testing 2......\n\n";

      User user2("Leonard");
      user2.change_password();
      user2.set_email();
      user2.print_info();

      cout << endl;
      User::print_n();
 }

 int main(){
  test();
 }

 

 

5.实验任务5

//account.h
#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
class SavingsAccount {            //储蓄账户类
    private:
        int id;                    //帐号
        double balance;            //余额
        double rate;            //存款的年利率
        int lastDate;            //上次变更余额的时期
        double accumulation;    //余额按日累加之和
        static double total;    //所有帐户的总金额
        //记录一笔账,date为日期,amount为金额,desc为说明
        void record(int date, double amount);
        //获得到指定日期为止的存款金额按日累积值
        double accumulate(int date) const {
            return accumulation + balance * (date - lastDate);
        }
    public:
        //构造函数
        SavingsAccount(int date, int id, double rate);
        int getId() const {return id;}
        double getBalance() const {return balance;}
        double getRate() const {return rate;}
        static double getTotal() {return total;}
        void deposit(int date, double amount);        //存入现金
        void withdraw(int date, double amount);        //取出现金
        //结算利息,每年1月1日调用一次该函数
        void settle(int date);
        //显示账户信息
        void show() const;
};
#endif //__ACCOUNT _H__

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

double SavingsAccount::total = 0;
//SavingsAccount类相关成员函数的实现
SavingsAccount::SavingsAccount(int date, int id, double rate)
    : id(id), balance(0), rate(rate), lastDate (date), accumulation(0) {
    cout << date << "\t#" << id << " is created" << endl;
}
void SavingsAccount::record(int date, double amount) {
    accumulation = accumulate(date);
    lastDate = date;
    amount = floor(amount * 100 + 0.5) / 100;        //保留小数点后两位
    balance += amount;
    total += amount;
    cout << date << "\t#" << id << "\t" << amount << "\t" << balance << endl;
}
void SavingsAccount::deposit(int date, double amount) {
    record(date, amount);
}
void SavingsAccount::withdraw(int date, double amount) {
    if ( amount > getBalance())
        cout << "Error: not enough money" << endl;
    else
        record(date, - amount);
}
void SavingsAccount::settle(int date) {
    double interest = accumulate(date) * rate / 365;
//计算年息
    if (interest != 0)
        record(date, interest);
    accumulation = 0;
}
void SavingsAccount::show() const {
    cout << "#" << id << "\tBalance: " << balance;
}

//5_11.cpp
#include "account.h"
#include <iostream>
using namespace std;
int main() {
    //建立几个帐户
    SavingsAccount sa0(1, 21325302, 0.015);
    SavingsAccount sa1(1, 58320212, 0.015);
    //几笔账目
    sa0.deposit(5, 5000) ;
    sa1.deposit(25, 10000);
    sa0.deposit(45, 5500);
    sa1.withdraw(60, 4000);
    //开户后第90天到了银行的计息日,结算所有账户的年息
    sa0.settle(90);
    sa1.settle(90);
    //输出各个帐户信息
    sa0.show();cout << endl;
    sa1.show();cout << endl;
    cout << "Total:" << SavingsAccount::getTotal() << endl;
    return 0;
}