实验3 类和对象_基础编程2

试验任务1：

  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";
}

window.hpp:

#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();
}

运行结果截图：

问题1：定义了botton和window类，使用了标准库的string和vector类，button类中使用了string类，window类中使用了botton类和vector类

问题2：不适合 有的是构造函数 有的是输出函数有变量 但是在输出类型void后加const 不会影响值的输出

问题3：输出*号将display输出的内容与其他内容隔断开

试验任务2：

#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();
}

运行结果截图：

问题1：第一行：初始化v1为5个42 第二行：v2复制v1 第三行：将v1的第一个42改成-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：t1，t2分别赋值为v1，v2的第一行元素，输出这一行最后一个元素

问题4：深复制，有const接口

实验任务3：

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;
}

 

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();
}

 

运行结果截图：

问题1：深复制

问题2：不能正常运行，报错：左操作数必须为左值；删除const后，运行结果正确

 问题3：代码能够运行。这样创建新vectorInt型需要额外空间

试验任务4：

matrix.hpp:

#pragma once

#include<iostream>
#include<cassert>

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

//类Matrix的声明
class Matrix {
public:
    Matrix(int n, int m);//构造函数，构造一个n*m的矩阵，初始值为 value
    Matrix(int n);//构造函数，构造一个n*n的矩阵，初始值为 value
    Matrix(const Matrix& x);//复制构造函数，使用已有的矩阵x构造 
    ~Matrix();

    void set(const double* pvalue);//用pvalue指向的连续内存块数据按行为矩阵赋值
    void clear();//把矩阵对象的值置0

    const double& at(int i, int j)const;//返回矩阵对象索引(i,j)的元素const
    double& at(int i, int j);

    int get_lines()const;//返回矩阵对象行数
    int get_cols()const;//返回矩阵对象列数

    void display()const;//按行显示矩阵对象元素值

private:
    int lines;//矩阵对象内元素行数
    int cols;//矩阵对象内元素列数
    double* ptr;
};

Matrix::Matrix(int n, int m) :lines(n), cols(m) {
    ptr = new double[n * m];
    for (int i = 0; i < n * m; ++i) {
        ptr[i] = 0.0;
    }
}

Matrix::Matrix(int n) :Matrix(n, n) {}

Matrix::Matrix(const Matrix& x) :lines(x.lines), cols(x.cols) {
    ptr = new double[lines * cols];
    for (int i = 0; i < lines * cols; ++i) {
        ptr[i] = x.ptr[i];
    }
}

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

void Matrix::set(const double* pvalue) {
    for (int i = 0; i < lines * cols; ++i) {
        ptr[i] = pvalue[i];
    }
}

void Matrix::clear() {
    for (int i = 0; i < lines * cols; ++i) {
        ptr[i] = 0.0;
    }
}

const double& Matrix::at(int i, int j)const {
    assert(i >= 0 && i < lines && j >= 0 && j < cols);
    return ptr[i * cols + j];
}

double& Matrix::at(int i, int j) {
    assert(i >= 0 && i < lines && j >= 0 && j < cols);
    return ptr[i * cols + j];
}

int Matrix::get_lines()const {
    return lines;
}

int Matrix::get_cols()const {
    return cols;
}

void Matrix::display()const {
    for (int i = 0; i < lines; ++i) {
        for (int j = 0; j < cols; ++j) {
            cout << at(i, j) << " ";
        }
        cout << endl;
    }
}

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();
}

运行结果截图：

 

实验任务5：

user.hpp

#pragma once

#include <iostream>
#include <string>

class User {
public:
    User(const std::string& username, const std::string& password = "", const std::string& email = "");

    void set_email();
    void change_password();
    void display() const;
    
private:
    std::string username_;
    std::string password_;
    std::string email_;
};

// 构造函数实现
User::User(const std::string& username, const std::string& password, const std::string& email)
    : username_(username), password_(password), email_(email) {}

void User::set_email() {
    std::string input_email;
    bool has_at_symbol = false;
    do {
        std::cout << "Enter email for " << username_ << ": ";
        std::cin >> input_email;
      
        for (char c : input_email) {
            if (c == '@') {
                has_at_symbol = true;
                break;
            }
        }
        if (!has_at_symbol) {
            std::cout << "无效的邮箱" << std::endl;
        }
    } while (!has_at_symbol);
    email_ = input_email;
}

void User::change_password() {
    std::string old_password;
    int attempts = 0;
    while (attempts < 3) {
        std::cout << "输入旧密码： " << username_ << ": ";
        std::cin >> old_password;
        if (old_password == password_) {
            std::string new_password;
            std::cout << "输入新密码： " << username_ << ": ";
            std::cin >> new_password;
            password_ = new_password;
            break;
        }
        else {
            attempts++;
            std::cout << "旧密码错误 " << 3 - attempts << std::endl;
        }
    }
    if (attempts == 3) {
        std::cout << "错误多次，稍后再试" << std::endl;
    }
}

void User::display() const {
    std::string password_display(password_.length(), '*');
    std::cout << "Username: " << username_ << ", Password: " << password_display << ", Email: " << email_;
}

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();
}

运行结果截图：

试验任务6：

 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

 

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__

 

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;
}

 

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();
}

 

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;
}