实验3

task1.

button.hpp

#pragma once

#include <iostream>
#include <string>

using std::string;
using std::cout;

// 按钮类
class Button {
public:
    Button(const string& text);
    string get_label() const;
    void click();

private:
    string label;
};

Button::Button(const string& text) : label{ text } {
}

inline string Button::get_label() const {
    return label;
}

void Button::click() {
    cout << "Button '" << label << "' clicked\n";
}

#pragma once
#include "button.hpp"
#include <vector>
#include <iostream>

using std::vector;
using std::cout;
using std::endl;

// 窗口类
class Window {
public:
    Window(const string& win_title);
    void display() const;
    void close();
    void add_button(const string& label);

private:
    string title;
    vector<Button> buttons;
};

Window::Window(const string& win_title) : title{ win_title } {
    buttons.push_back(Button("close"));
}

inline void Window::display() const {
    string s(40, '*');

    cout << s << endl;
    cout << "window title: " << title << endl;
    cout << "It has " << buttons.size() << " buttons: " << endl;
    for (const auto& i : buttons)
        cout << i.get_label() << " button" << endl;
    cout << s << endl;
}

void Window::close() {
    cout << "close window '" << title << "'" << endl;
    buttons.at(0).click();
}

void Window::add_button(const string& label) {
    buttons.push_back(Button(label));
}

task1.cpp

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

using std::cout;
using std::cin;

void test() {
    Window w1("new window");
    w1.add_button("maximize");
    w1.display();
    w1.close();
}

int main() {
    cout << "用组合类模拟简单GUI:\n";
    test();
}

问题一：自定义了两个类Button和Window,运用了标准库的类：vector、cout、string。Window类中包含了一个 vector<Button> 类型的成员变量buttons,因此Window类和Button类之间存在组合关系。

问题二：Button类中void click()修改了标准输出，不能改为const或设置为inline。Window类中void add_button(const string &label)可以设置为inline，其构造函数为简单函数。

问题三：string s(40, '*');  输出40个“*”符号作为分隔线。

task2.

task2.cpp

#include <iostream>
#include <vector>

using namespace std;

void output1(const vector<int> &v) {
    for(auto &i: v)
        cout << i << ", ";
    cout << "\b\b \n";
}

void output2(const vector<vector<int>> v) {
    for(auto &i: v) {
        for(auto &j: i)
            cout << j << ", ";
        cout << "\b\b \n";
    }
}

void test1() {
    vector<int> v1(5, 42);
    const vector<int> v2(v1);

    v1.at(0) = -999;
    cout << "v1: ";  output1(v1);
    cout << "v2: ";  output1(v2);
    cout << "v1.at(0) = " << v1.at(0) << endl;
    cout << "v2.at(0) = " << v2.at(0) << endl;
}

void test2() {
    vector<vector<int>> v1{{1, 2, 3}, {4, 5, 6, 7}};
    const vector<vector<int>> v2(v1);

    v1.at(0).push_back(-999);
    cout << "v1: \n";  output2(v1);
    cout << "v2: \n";  output2(v2);

    vector<int> t1 = v1.at(0);
    cout << t1.at(t1.size()-1) << endl;
    
    const vector<int> t2 = v2.at(0);
    cout << t2.at(t2.size()-1) << endl;
}

int main() {
    cout << "测试1:\n";
    test1();

    cout << "\n测试2:\n";
    test2();
}

问题1：先创建了一个名为v1的vector，包含5跟都是42的元素，然后创建一个名为v2的vector，并用v1来将其初始化，最后将v1的第一个元素改成了-999.

问题·2：第一行：初始化v1 相当于二维数组 第二行：v2为常量复制v1  第三行：将v1第一行中的最后一个改成-999

问题3：创建了一个名为t1的的vector，并用v1的第一个元素来将其初始化，然后输出t1的最后一个元素的值；创建了一个名为t2的vector，并用v2的第一个元素来将其初始化，然后输出t2的最后一个元素的值，并且因为t2前的const所以t2不能被修改

问题4:

1.深复制

2.需要

task3

task3.cpp

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

using std::cout;
using std::cin;

void output(const vectorInt& vi) {
    for (auto i = 0; i < vi.get_size(); ++i)
        cout << vi.at(i) << ", ";
    cout << "\b\b \n";
}


void test1() {
    int n;
    cout << "Enter n:";
    cin >> n;

    vectorInt x1(n);
    for (auto i = 0; i < n; ++i)
        x1.at(i) = i * i;
    cout << "x1:"; output(x1);

    vectorInt x2(n, 42);
    vectorInt x3(x2);
    x2.at(0) = -999;
    cout << "x2:"; output(x2);
    cout << "x3:"; output(x3);
}

void test2() {
    const vectorInt x(5, 42);
    vectorInt y(10, 0);

    cout << "y:"; output(y);
    y.assign(x);
    cout << "y:"; output(y);

    cout << "x.at(0)=" << x.at(0) << endl;
    cout << "y.at(0)=" << y.at(0) << endl;
}

int main() {
    cout << "测试1：\n";
    test1();

    cout << "\n测试2：\n";
    test2();
}

vectorint.hpp

#pragma once

#include<iostream>
#include<cassert>

using std::cout;
using std::endl;

//动态int数组对象类
class vectorInt {
public:
    vectorInt(int n);
    vectorInt(int n, int value);
    vectorInt(const vectorInt& vi);
    ~vectorInt();

    int& at(int index);
    const int& at(int index)const;

    vectorInt& assign(const vectorInt& v);
    int get_size()const;

private:
    int size;
    int* ptr;
};

vectorInt::vectorInt(int n) :size{ n }, ptr{ new int[size] } {
}

vectorInt::vectorInt(int n, int value) :size{ n }, ptr{ new int[size] } {
    for (auto i = 0; i < size; ++i)
        ptr[i] = value;
}

vectorInt::vectorInt(const vectorInt& vi) :size{ vi.size }, ptr{ new int[size] } {
    for (auto i = 0; i < size; ++i)
        ptr[i] = vi.ptr[i];
}

vectorInt::~vectorInt() {
    delete[]ptr;
}

const int& vectorInt::at(int index)const {
    assert(index >= 0 && index < size);

    return ptr[index];
}

int& vectorInt::at(int index) {
    assert(index >= 0 && index < size);

    return ptr[index];
}

vectorInt& vectorInt::assign(const vectorInt& v) {
    delete[] ptr;

    size = v.size;
    ptr = new int[size];

    for (int i = 0; i < size; ++i)
        ptr[i] = v.ptr[i];

    return *this;
}

int vectorInt::get_size()const {
    return size;
}

问题1：深复制

问题2：不能将返回值类型改成int而非int&，由于at()现在返回的是值，因此无法通过返回的值来修改原始容器中的元素。

如果把line18返回值类型前面的const删掉，则不能修改任何成员变量。

问题3：不能。assign()返回值而不是引用,无法连续调用多个返回引用的成员函数。

task.4

matrix.hpp

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

using std::cin;
using std::cout;

void output(const vectorInt &vi) {
    for(auto i = 0; i < vi.get_size(); ++i)
        cout << vi.at(i) << ", ";
    cout << "\b\b \n";
}


void test1() {
    int n;
    cout << "Enter n: ";
    cin >> n;

    vectorInt x1(n);
    for(auto i = 0; i < n; ++i)
        x1.at(i) = i*i;
    cout << "x1: ";  output(x1);

    vectorInt x2(n, 42);
    vectorInt x3(x2);
    x2.at(0) = -999;
    cout << "x2: ";  output(x2);
    cout << "x3: ";  output(x3);
}

void test2() {
    const vectorInt  x(5, 42);
    vectorInt y(10, 0);

    cout << "y: ";  output(y);
    y.assign(x);
    cout << "y: ";  output(y);
    
    cout << "x.at(0) = " << x.at(0) << endl;
    cout << "y.at(0) = " << y.at(0) << endl;
}

int main() {
    cout << "测试1: \n";
    test1();

    cout << "\n测试2: \n";
    test2();
}

task4.cpp

#include "matrix.hpp"
#include <iostream>
#include <cassert>

using std::cin;
using std::cout;
using std::endl;


const int N = 1000;

// 输出矩阵对象索引为index所在行的所有元素
void output(const Matrix &m, int index) {
    assert(index >= 0 && index < m.get_lines());

    for(auto j = 0; j < m.get_cols(); ++j)
        cout << m.at(index, j) << ", ";
    cout << "\b\b \n";
}


void test1() {
    double x[1000] = {1, 2, 3, 4, 5, 6, 7, 8, 9};

    int n, m;
    cout << "Enter n and m: ";
    cin >> n >> m;

    Matrix m1(n, m);    // 创建矩阵对象m1, 大小n×m
    m1.set(x);          // 用一维数组x的值按行为矩阵m1赋值

    Matrix m2(m, n);    // 创建矩阵对象m1, 大小m×n
    m2.set(x);          // 用一维数组x的值按行为矩阵m1赋值

    Matrix m3(2);       // 创建一个2×2矩阵对象
    m3.set(x);          // 用一维数组x的值按行为矩阵m4赋值

    cout << "矩阵对象m1: \n";   m1.display();  cout << endl;
    cout << "矩阵对象m2: \n";   m2.display();  cout << endl;
    cout << "矩阵对象m3: \n";   m3.display();  cout << endl;
}

void test2() {
    Matrix m1(2, 3);
    m1.clear();
    
    const Matrix m2(m1);
    m1.at(0, 0) = -999;

    cout << "m1.at(0, 0) = " << m1.at(0, 0) << endl;
    cout << "m2.at(0, 0) = " << m2.at(0, 0) << endl;
    cout << "矩阵对象m1第0行: "; output(m1, 0);
    cout << "矩阵对象m2第0行: "; output(m2, 0);
}

int main() {
    cout << "测试1: \n";
    test1();

    cout << "测试2: \n";
    test2();
}

task5

user.cpp

1  #pragma once
 2   #include <iostream>
 3   #include <string>
 4  #include <vector>
 5   
 6   using std::string;
 7   using std::cout;
 8   using std::endl;
 9   using std::vector;
10  
11  class User {
12 public:
13      User(const string& name, const string& password = "123456", const string& email = "");
14      void set_email();
15      void change_password();
16      void display();
17  private:
18      string name;
19      string password;
20      string email;
21  };
22  
23  User::User(const string& name, const string& password, const string& email) : name{ name }, password{ password }, email{ email } {}
24  
25  void User::set_email() {
26      string input;
27      bool c = false;
28      cout << "Enter email address: ";
29      do {
30          
31          std::cin >> input;
32          size_t pos = input.find('@');
33          if (pos != string::npos) {
34              c = true;
35          }
36          else {
37              cout << "illegal email. Please re-enter email: ";
38          }
39      } while (!c);
40      email = input;
41      cout << "email is set successfully..." << endl;
42  }
43  
44  void User::change_password() {
45      string old_password;
46      string new_password;
47      int cnt = 0;
48      bool correct = false;
49      cout << "Enter old password: ";
50      do {
51          
52          std::cin >> old_password;
53          if (old_password == password) {
54              correct = true;
55          }
56          else {
57              cnt++;
58              if (cnt == 3) {
59                  cout << "password input error. Please try after a while." << endl;
60                  return;
61              }
62              cout << "password input error. Please re-enter again: ";
63          }
64      } while (!correct);
65      cout << "Enter new password: ";
66      std::cin >> new_password;
67      password = new_password;
68      cout << "new password is set successfully..." << endl;
69  }
70  
71  void User::display() {
72      cout << "name: " << name << endl;
73      string showpassword(password.length(), '*');
74      cout << "pass: " << showpassword << endl;
75      cout << "email: " << email << endl;
76  }

user.cpp

task5.cpp

#include "user.hpp"
#include <iostream>
#include <vector>
#include <string>

using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::string;

void test() {
    vector<User> user_lst;

    User u1("Alice", "2024113", "Alice@hotmail.com");
    user_lst.push_back(u1);
    cout << endl;

    User u2("Bob");
    u2.set_email();
    u2.change_password();
    user_lst.push_back(u2);
    cout << endl;

    User u3("Hellen");
    u3.set_email();
    u3.change_password();
    user_lst.push_back(u3);
    cout << endl;

    cout << "There are " << user_lst.size() << " users. they are: " << endl;
    for(auto &i: user_lst) {
        i.display();
        cout << endl;
    }
}

int main() {
    test();
}

task6

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;//获得当月有多少天
         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 distance(const Date & date) const {
        return totalDays - date.totalDays;
    }
};
 #endif //__DATE_H__

date.cpp 

//date.cpp
#include "date.h"
#include <iostream>
#include <cstdlib>
using namespace std;
namespace {
    //namespace使下面的定义只在当前文件中有效
        const int DAYS_BEFORE_MONTH[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 356 };
}
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();
}

account.h

//account.h
#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
#include "date.h"
#include <string>
class SavingsAccount {//储蓄账户类
 private:
    std::string id;//账号
        double balance;//余额
        double rate;//存款的年利率
        Date lastDate;//上次变更余额的时期
        double accumulation;//按日累加以和
        static double total;//所有账户的总金额
             //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;
    //获得指定日期为止的存款金额按日累增值
        double accumulate(const Date & date) const {
        return accumulation + balance * date.distance(lastDate);
    }
public:
    //构造函数
        SavingsAccount(const Date & date, const std::string & id, double rate);//获得账号
        const std::string & getId() const { return id; } //获得余额
        double getBalance() const { return balance; } //获得年利率
        double getRate() const { return rate; }
    static double getTotal() { return total; }//存入现金
 void deposit(const Date & date, double amount, const std::string & desc);//取出现金
        void withdraw(const Date & date, double amount, const std::string & desc);//结算利息，每年1月1日调用一次该函数
        void settle(const Date & date);
        //显示账户信息
        void show() const;
};
#endif //__ACCOUNT_H__#pragma once

account.cpp

//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(const Date &date,const string &id,double rate):id(id),balance(0),rate(rate),lastDate(date),accumulation(0){
    date.show();
    cout << "\t#" << id << " created" << endl;
}
void SavingsAccount::record(const Date & date, double amount, const string & desc) {
    accumulation = accumulate(date);
    lastDate = date;
    amount = floor(amount * 100 + 0.5) / 100;
    //保留小数点后两位
        balance += amount;
    total += amount;
    date.show();
    cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;
}
void SavingsAccount::error(const string & msg) const {
    cout << "Error(#" << id << "): " << msg << endl;
}
void SavingsAccount::deposit(const Date & date, double amount, const string & desc) {
    record(date, amount, desc);
}
void SavingsAccount::withdraw(const Date & date, double amount, const string & desc) {
    if (amount > getBalance())
        error("not enough money");
    else
        record(date, -amount, desc);
}
void SavingsAccount::settle(const Date & date) {
    double interest = accumulate(date) * rate / date.distance(Date(date.getYear() - 1, 1, 1));
    if (interest != 0)
        record(date, interest, "interest");
    accumulation = 0;
}
void SavingsAccount::show() const {
    cout << "ID: " << id << "\tBalance: " << balance;
}

 task6.cpp

//6.25.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 accounts[] = {
       SavingsAccount(date, "03755217", 0.015),
       SavingsAccount(date, "02342342", 0.015)
     };
    //几笔账目
        accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
    accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
    accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
    accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
    //结算所有账户并输出各个账户信息
        cout << endl;
    for (int i = 0; i < sizeof(accounts) / sizeof(SavingsAccount); i++) {
        accounts[i].settle(Date(2009, 1, 1));
        accounts[i].show();
        cout << endl;
    }
    cout << "Total: " << SavingsAccount::getTotal() << endl;
    return 0;
}