实验3 类和对象_基础编程2

test1:

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();
}

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));
}

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";
}

运行结果：

问题1：

自定义两个类，用到了标准库三个类，Window 和Button有组合关系

2：

1.click函数
1.答案：不适合加const和inline。
2.理由：逻辑上表示按钮状态改变，与可变行为相关，不适合const；涉及cout输出，相对复杂，内联可能导致代码膨胀。
2.close函数
1.答案：适合加const，不适合inline。
2.理由：未修改对象内部状态，加const可提高可读性；涉及cout输出和调用其他函数，内联会致代码膨胀。
3.add_button函数
1.答案：不适合加const和inline。
2.理由：修改成员变量，不符合const；向向量添加元素复杂，inline可能致代码膨胀。

3：

声明s是长度为40的字符串，并将每个字符赋值为*

test2:

#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：

问题1.

为v1申请一片储存整型变量的空间并赋值5，42；
为v2申请一片储存整型变量的空间并将v1中的元素赋值给v2；
将v1中的第一个元素赋值为-999；
2.
为v1申请一片储存储存整型数据的空间的空间；
为v2申请一片储存储存整型数据的空间的空间并将v1中的元素赋值给v2；
在v1中第一个空间的末尾插入值为-999的整型元素；
3.
为t1一片储存整型数据的空间并将v1中第一个空间中的的元素赋值给v2；
输出t1中最后一个元素的值并换行；
为t2一片储存整型数据的空间并将v2中第一个空间中的的元素赋值给v2，并且声明t2不可被修改；
输出t2中最后一个元素的值并换行；

test3:

task3.cpp:

#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();
}

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;       // ptr指向包含size个int的数组
};

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;       // 释放对象中ptr原来指向的资源

    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;
}

运行结果：

问题1.

浅复制
2.
不能正常运行，返回值不可以改成int类型，测试1中对返回值进行了赋值操作。
有安全隐患，测试可能有改变返回值的操作
3.
可以

test4:

matrix.hpp：

#pragma once

#include <iostream>
#include <cassert>
#include <vector>

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

    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;
};

// 类Matrix的实现：待补足
// xxx
Matrix::Matrix(int n, int m) :lines{ n }, cols{ m } {
    ptr = new double [lines * cols];
}

Matrix::Matrix(int n) :lines{ n }, cols{ n } {
    ptr = new double[lines * cols];
}

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

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

double& Matrix::at(int i, int j)
{
    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 << ptr[i * cols + 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：

 

test5:

user.hpp：

#pragma once

#include <iostream>
#include <cassert>
#include <string>

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

class User {
public:
    User(std::string n, std::string p = "123456", std::string e = "") :name{ n }, password{ p }, email{ e } {};
    ~User()=default;

    void set_email();
    void change_password();                         
    void display() const;     

private:
    std::string name;
    std::string password;
    std::string email;
};
void User::set_email() {
    std::string t;
    cout << "Please enter the email:";
    cin >> t;
    auto i = std::find(t.begin(), t.end(), '@');
    if (i != t.end()) { email = t; cout << "OK" << endl; }
    else cout << "ERROR" << endl;
}
void User::change_password() {
    std::string t;
    cout << "Please enter the old password:";
    for (int i = 0; i < 3; i++)
    {
        cin >> t;
        if (t == password) {
            cout << "Right,please enter the new password:";
            cin >> password;
            cout << "OK;";
            break;
        }
        else if (i < 2) cout << "Wrong,please try again:";
        else cout << "Wrong,please try after afew minute.";
    }
}
void User::display() const{
    cout << "Name:" << name << endl;
    cout << "Email:" << email << endl;
    cout << "Password:";
    for (int i = 0; i < password.length(); i++)
    {
        cout << '*';
    }
    cout << endl;
}

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：

 

test6:

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;
    //余额按日累加之和
    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;
    //获得到指定日期为止的存款金额按日累积值
    double accumulate(const Date& date) const {
        return accumulation + balance * date.dístance(lastDate);
    }
public:
    //构造函数
    SavingsAccount(const Date& date, const std::string& id, double rate);
    const std::string& getId() const { return id; }
    double getBalance() const { return balance; }
    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__

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;
    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//计算年息
        / date.dístance(Date(date.getYear() - 1, 1, 1));
    if (interest != 0)
        record(date, interest, "interest");
    accumulation = 0;
}
void SavingsAccount::show() const {
    cout << id << "\tBalance:" << balance;
}

data.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日开始的第儿天
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
    //计算两个日期之间差多少天
    int dístance(const Date& date) const {
        return totalDays - date.totalDays;
    }
};
#endif / / _DATE_H__

data.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
    //存储平年中的某个月1日之前有多少天，为便于getMaxDay函数的实现，该数组多出一项
    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();
}

 

6_25.cpp

#include "account.h"
#include <iostream>
using namespace std;
int main() {
    //起始日期
    Date date(2008, 11, 1);
    //建立几个账户
    SavingsAccount accounts[] = {
    SavingsAccount(date,"03755217",0.015),
    SavingsAccount(date, "02342342", 0.015)
    };
    const int n = sizeof(accounts) / sizeof(SavingsAccount); //账户总数
    //11月份的几笔账目
    accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
    accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
    //12月份的几笔账目
    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 < n; i++) {
        accounts[i].settle(Date(2009, 1, 1));
        accounts[i].show();
        cout << endl;
    }
    cout << "Total: " << SavingsAccount::getTotal() << endl;
    return 0;
}