实验3

任务1

button.hpp

 1 #pragma once
 2 
 3 #include <iostream>
 4 #include <string>
 5 
 6 using std::string;
 7 using std::cout;
 8 
 9 // 按钮类
10 class Button {
11 public:
12     Button(const string &text);
13     string get_label() const;
14     void click();
15 
16 private:
17     string label;
18 };
19 
20 Button::Button(const string &text): label{text} {
21 }
22 
23 inline string Button::get_label() const {
24     return label;
25 }
26 
27 void Button::click() {
28     cout << "Button '" << label << "' clicked\n";
29 }

window.hpp

 1 #pragma once
 2 #include "button.hpp"
 3 #include <vector>
 4 #include <iostream>
 5 
 6 using std::vector;
 7 using std::cout;
 8 using std::endl;
 9 
10 // 窗口类
11 class Window{
12 public:
13     Window(const string &win_title);
14     void display() const;
15     void close();
16     void add_button(const string &label);
17 
18 private:
19     string title;
20     vector<Button> buttons;
21 };
22 
23 Window::Window(const string &win_title): title{win_title} {
24     buttons.push_back(Button("close"));
25 }
26 
27 inline void Window::display() const {
28     string s(40, '*');
29 
30     cout << s << endl;
31     cout << "window title: " << title << endl;
32     cout << "It has " << buttons.size() << " buttons: " << endl;
33     for(const auto &i: buttons)
34         cout << i.get_label() << " button" << endl;
35     cout << s << endl;
36 }
37 
38 void Window::close() {
39     cout << "close window '" << title << "'" << endl;
40     buttons.at(0).click();
41 }
42 
43 void Window::add_button(const string &label) {
44     buttons.push_back(Button(label));
45 }

task1.cpp

 1 #include "window.hpp"
 2 #include <iostream>
 3 
 4 using std::cout;
 5 using std::cin;
 6 
 7 void test() {
 8     Window w1("new window");
 9     w1.add_button("maximize");
10     w1.display();
11     w1.close();
12 }
13 
14 int main() {
15     cout << "用组合类模拟简单GUI:\n";
16     test();
17 }

运行结果：

问题：

问题1：这个模拟简单GUI的示例代码中，自定义了几个类？使用到了标准库的哪几个类？，哪些类和类之间存在组合关系？

答：自定义了两个类Button和Window。用的了标准库类string和vector。Window和Button类之间存在组合关系。

问题2：在自定义类Button和Window中，有些成员函数定义时加了const, 有些设置成了inline。如果你是类的设计者，目前那些没有加const或没有设置成inline的，适合添加const，适合设置成 inline吗？陈述你的答案和理由。

适合添加const，因为它不会修改类的状态。适合添加inline，实现简单，代码量少。

问题3：类Window的定义中，有这样一行代码，其功能是？

创建了一个名为s的string对象，初始化又40个‘*’字符组成的字符串

任务2

task2.cpp

 1 #include <iostream>
 2 #include <vector>
 3 
 4 using namespace std;
 5 
 6 void output1(const vector<int> &v) {
 7     for(auto &i: v)
 8         cout << i << ", ";
 9     cout << "\b\b \n";
10 }
11 
12 void output2(const vector<vector<int>> v) {
13     for(auto &i: v) {
14         for(auto &j: i)
15             cout << j << ", ";
16         cout << "\b\b \n";
17     }
18 }
19 
20 void test1() {
21     vector<int> v1(5, 42);
22     const vector<int> v2(v1);
23 
24     v1.at(0) = -999;
25     cout << "v1: ";  output1(v1);
26     cout << "v2: ";  output1(v2);
27     cout << "v1.at(0) = " << v1.at(0) << endl;
28     cout << "v2.at(0) = " << v2.at(0) << endl;
29 }
30 
31 void test2() {
32     vector<vector<int>> v1{{1, 2, 3}, {4, 5, 6, 7}};
33     const vector<vector<int>> v2(v1);
34 
35     v1.at(0).push_back(-999);
36     cout << "v1: \n";  output2(v1);
37     cout << "v2: \n";  output2(v2);
38 
39     vector<int> t1 = v1.at(0);
40     cout << t1.at(t1.size()-1) << endl;
41     
42     const vector<int> t2 = v2.at(0);
43     cout << t2.at(t2.size()-1) << endl;
44 }
45 
46 int main() {
47     cout << "测试1:\n";
48     test1();
49 
50     cout << "\n测试2:\n";
51     test2();
52 }

运行结果：

任务3

vectorlnt.hpp

 1  #pragma once
 2  
 3  #include <iostream>
 4  #include <cassert>
 5  
 6  using std::cout;
 7  using std::endl; 
 8  // 动态int数组对象类
 9 class vectorInt{
10 public:
11     vectorInt(int n);
12     vectorInt(int n, int value);
13     vectorInt(const vectorInt &vi);
14     ~vectorInt();
15 
16     int& at(int index);
17     const int& at(int index) const;
18 
19     vectorInt& assign(const vectorInt &v);
20     int get_size() const;
21 private:
22     int size;
23     int *ptr;       // ptr指向包含size个int的数组
24 };
25 vectorInt::vectorInt(int n): size{n}, ptr{new int[size]} {
26 }
27 vectorInt::vectorInt(int n, int value): size{n}, ptr{new int[size]} {
28     for(auto i = 0; i < size; ++i)
29        ptr[i] = value;
30 vectorInt::vectorInt(const vectorInt &vi): size{vi.size}, ptr{new int[size]} {
31     for(auto i = 0; i < size; ++i)
32         ptr[i] = vi.ptr[i];
33 }
34 vectorInt::~vectorInt() {
35    delete [] ptr;
36 }
37 
38 const int& vectorInt::at(int index) const {
39    assert(index >= 0 && index < size);
40 
41     return ptr[index];
42 }
43 
44 int& vectorInt::at(int index) {
45     assert(index >= 0 && index < size);
46 
47     return ptr[index];
48 }
49 vectorInt& vectorInt::assign(const vectorInt &v) {  
50     delete[] ptr;       // 释放对象中ptr原来指向的资源
51 
52     size = v.size;
53     ptr = new int[size];
54 
55     for(int i = 0; i < size; ++i)
56         ptr[i] = v.ptr[i];
57 
58     return *this;       //this现在指向正在初始化的对象，*this即为这个对象
59 }
60 
61 int vectorInt::get_size() const {
62     return size;
63 }

task3.cpp

 1 #include "vectorInt.hpp"
 2  #include <iostream>
 3  
 4 using std::cin;
 5 using std::cout;
 6 void output(const vectorInt &vi) {
 7    for(auto i = 0; i < vi.get_size(); ++i)
 8         cout << vi.at(i) << ", ";
 9     cout << "\b\b \n";
10 }
11 
12  
13 void test1() {
14     int n;
15     cout << "Enter n: ";
16     cin >> n;
17  
18      vectorInt x1(n);
19      for(auto i = 0; i < n; ++i)
20          x1.at(i) = i*i;
21      cout << "x1: ";  output(x1);
22  
23      vectorInt x2(n, 42);
24      vectorInt x3(x2);
25      x2.at(0) = -999;
26      cout << "x2: ";  output(x2);
27      cout << "x3: ";  output(x3);
28  }
29  
30  
31  void test2() {
32      const vectorInt  x(5, 42);
33      vectorInt y(10, 0);
34 
35      cout << "y: ";  output(y);
36      y.assign(x);
37      cout << "y: ";  output(y);
38      
39      cout << "x.at(0) = " << x.at(0) << endl;
40      cout << "y.at(0) = " << y.at(0) << endl;
41  }
42  
43  int main() {
44      cout << "测试1: \n";
45      test1();
46  
47      cout << "\n测试2: \n";
48      test2();
49  }

运行结果截图：

问题：

1.深复制

2.不能，会有潜在安全隐患

3.返回值类型为 vectorInt& 时：返回当前对象的引用 *this，意味着调用 assign() 后，调用者获得的是调用对象本身。这允许方法链调用

任务4

matrix.hpp

 1 #pragma once
 2 
 3 #include <iostream>
 4 #include <cassert>
 5 
 6 using std::cout;
 7 using std::endl;
 8 
 9 // 类Matrix的声明
10 class Matrix {
11 public:
12     Matrix(int n, int m);           // 构造函数，构造一个n*m的矩阵, 初始值为value
13     Matrix(int n);                  // 构造函数，构造一个n*n的矩阵, 初始值为value
14     Matrix(const Matrix &x);        // 复制构造函数， 使用已有的矩阵X构造
15     ~Matrix();
16 
17     void set(const double *pvalue);         // 用pvalue指向的连续内存块数据按行为矩阵赋值
18     void clear();                           // 把矩阵对象的值置0
19     
20     const double& at(int i, int j) const;   // 返回矩阵对象索引(i,j)的元素const引用
21     double& at(int i, int j);               // 返回矩阵对象索引(i,j)的元素引用
22     
23     int get_lines() const;                  // 返回矩阵对象行数
24     int get_cols() const;                   // 返回矩阵对象列数
25 
26     void display() const;                    // 按行显示矩阵对象元素值
27 
28 private:
29     int lines;      // 矩阵对象内元素行数
30     int cols;       // 矩阵对象内元素列数
31     double *ptr;
32 };
33 
34 // 构造函数：创建一个 n 行 m 列的矩阵
35 Matrix::Matrix(int n, int m): lines(n), cols(m), ptr(new double[n * m]()) {}
36 
37 // 构造函数：创建一个 n 行 n 列的方阵
38 Matrix::Matrix(int n): lines(n), cols(n), ptr(new double[n * n]()) {}
39 
40 // 拷贝构造函数
41 Matrix::Matrix(const Matrix &x): lines(x.lines), cols(x.cols), ptr(new double[x.lines * x.cols]) {
42     for (int i = 0; i < lines * cols; ++i)
43         ptr[i] = x.ptr[i];
44 }
45 
46 // 析构函数
47 Matrix::~Matrix() {
48     delete[] ptr;
49 }
50 
51 // 设置矩阵的值
52 void Matrix::set(const double *pvalue) {
53     for (int i = 0; i < lines * cols; ++i)
54         ptr[i] = pvalue[i];
55 }
56 
57 // 清空矩阵
58 void Matrix::clear() {
59     for (int i = 0; i < lines * cols; ++i)
60         ptr[i] = 0.0;
61 }
62 
63 // 访问矩阵中的元素
64 const double& Matrix::at(int i, int j) const {
65     assert(i >= 0 && i < lines && j >= 0 && j < cols);
66     return ptr[i * cols + j];
67 }
68 
69 // 访问矩阵中的元素（可写）
70 double& Matrix::at(int i, int j) {
71     assert(i >= 0 && i < lines && j >= 0 && j < cols);
72     return ptr[i * cols + j];
73 }
74 
75 // 获取矩阵的行数
76 int Matrix::get_lines() const {
77     return lines;
78 }
79 
80 // 获取矩阵的列数
81 int Matrix::get_cols() const {
82     return cols;
83 }
84 
85 // 显示矩阵内容
86 void Matrix::display() const {
87     for (int i = 0; i < lines; ++i) {
88         for (int j = 0; j < cols; ++j) {
89             cout << at(i, j) << " ";
90         }
91         cout << endl;
92     }
93 }

task4.cpp

 1 #include "matrix.hpp"
 2 #include <iostream>
 3 #include <cassert>
 4 
 5 using std::cin;
 6 using std::cout;
 7 using std::endl;
 8 
 9 
10 const int N = 1000;
11 
12 // 输出矩阵对象索引为index所在行的所有元素
13 void output(const Matrix &m, int index) {
14     assert(index >= 0 && index < m.get_lines());
15 
16     for(auto j = 0; j < m.get_cols(); ++j)
17         cout << m.at(index, j) << ", ";
18     cout << "\b\b \n";
19 }
20 
21 
22 void test1() {
23     double x[1000] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
24 
25     int n, m;
26     cout << "Enter n and m: ";
27     cin >> n >> m;
28 
29     Matrix m1(n, m);    // 创建矩阵对象m1, 大小n×m
30     m1.set(x);          // 用一维数组x的值按行为矩阵m1赋值
31 
32     Matrix m2(m, n);    // 创建矩阵对象m1, 大小m×n
33     m2.set(x);          // 用一维数组x的值按行为矩阵m1赋值
34 
35     Matrix m3(2);       // 创建一个2×2矩阵对象
36     m3.set(x);          // 用一维数组x的值按行为矩阵m4赋值
37 
38     cout << "矩阵对象m1: \n";   m1.display();  cout << endl;
39     cout << "矩阵对象m2: \n";   m2.display();  cout << endl;
40     cout << "矩阵对象m3: \n";   m3.display();  cout << endl;
41 }
42 
43 void test2() {
44     Matrix m1(2, 3);
45     m1.clear();
46     
47     const Matrix m2(m1);
48     m1.at(0, 0) = -999;
49 
50     cout << "m1.at(0, 0) = " << m1.at(0, 0) << endl;
51     cout << "m2.at(0, 0) = " << m2.at(0, 0) << endl;
52     cout << "矩阵对象m1第0行: "; output(m1, 0);
53     cout << "矩阵对象m2第0行: "; output(m2, 0);
54 }
55 
56 int main() {
57     cout << "测试1: \n";
58     test1();
59 
60     cout << "测试2: \n";
61     test2();
62 }

运行结果截图：

任务5

User.hpp

 1 #pragma once
 2 
 3 #include <iostream>
 4 #include <string>
 5 
 6 using std::string;
 7 using std::cout;
 8 using std::cin;
 9 using std::endl;
10 
11 class User {
12 public:
13     // 构造函数
14     User(const string &name, const string &password = "123456", const string &email = "")
15         : name{name}, password{password}, email{email} {}
16 
17     // 设置邮箱
18     void set_email() {
19         string input_email;
20         cout << "Enter email address:";
21         while (true) {
22             cin >> input_email;
23             if (is_valid_email(input_email)) {
24                 email = input_email;
25                 break;
26             } else {
27                 cout << "illegal email.Please re-enter email:";
28             }
29         }
30     }
31 
32     // 修改密码
33     void change_password() {
34         string old_password;
35         int attempts = 3;
36 
37         while (attempts > 0) {
38             cout << "Enter old password";
39             cin >> old_password;
40             if (old_password == password) {
41                 cout << "Enter new password:";
42                 cin >> password;
43                 cout << "new password is set successfully..." << endl;
44                 return;
45             } else {
46                 attempts--;
47                 cout << "password input error.Please re-enter angain:" << attempts << endl;
48             }
49         }
50         cout << "password input error.Please try after a while." << endl;
51     }
52 
53     // 显示用户信息
54     void display() const {
55         cout << "name: " << name << endl;
56         cout << "pass: " << string(password.size(), '*') << endl;
57         cout << "email: " << (email.empty() ? "未设置" : email) << endl;
58     }
59 
60 private:
61     // 数据成员
62     string name;
63     string password;
64     string email;
65 
66     // 检查邮箱格式是否有效
67     bool is_valid_email(const string &email) const {
68         return email.find('@') != string::npos;
69     }
70 };

task5.cpp

 1 #include "user.hpp"
 2 #include <iostream>
 3 #include <vector>
 4 #include <string>
 5 
 6 using std::cin;
 7 using std::cout;
 8 using std::endl;
 9 using std::vector;
10 using std::string;
11 
12 void test() {
13     vector<User> user_lst;
14 
15     User u1("Alice", "2024113", "Alice@hotmail.com");
16     user_lst.push_back(u1);
17     cout << endl;
18 
19     User u2("Bob");
20     u2.set_email();
21     u2.change_password();
22     user_lst.push_back(u2);
23     cout << endl;
24 
25     User u3("Hellen");
26     u3.set_email();
27     u3.change_password();
28     user_lst.push_back(u3);
29     cout << endl;
30 
31     cout << "There are " << user_lst.size() << " users. they are: " << endl;
32     for(auto &i: user_lst) {
33         i.display();
34         cout << endl;
35     }
36 }
37 
38 int main() {
39     test();
40 }

运行结果截图：

任务6

date.h

 1 #ifndef __DATE_H__
 2 #define __DATE_H__
 3 class Date {
 4 private:
 5     int year;
 6     int month;
 7     int day;
 8     int totalDays;
 9 public:
10     Date(int year, int month, int day);
11     int getYear()const { return year; }
12     int getMonth()const { return month; }
13     int getDay()const { return day; }
14     int getMaxDay()const;
15     bool isLeapYear()const {
16         return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
17 
18     }
19     void show() const;
20     int distance(const Date& date)const {
21         return totalDays - date.totalDays;
22 
23     }
24 
25 };
26 #endif

date.cpp

 1 #include"date.h"
 2 #include<iostream>
 3 #include<cstdlib>
 4 using namespace std;
 5 namespace {
 6     const int DAYS_BEFIRE_MONTH[] = { 0,31,59,90,120,151,181,212,243,273,304 ,334,365 };
 7 
 8 }
 9 Date::Date(int year, int month, int day) :year(year), month(month), day(day) {
10     if (day <= 0 || day > getMaxDay()) {
11         cout << "Invalid date: ";
12         show();
13         cout << endl;
14         exit(1);
15 
16     }
17     int years = year - 1;
18     totalDays = years * 365 + years / 4 - years / 100 + years / 400 + DAYS_BEFIRE_MONTH[month - 1] + day;
19     if (isLeapYear() && month > 2) totalDays++;
20 
21 }
22 int Date::getMaxDay()const {
23     if (isLeapYear() && month == 2)
24         return 29;
25     else return DAYS_BEFIRE_MONTH[month] - DAYS_BEFIRE_MONTH[month - 1];
26 
27 }
28 void Date::show()const {
29     cout << getYear() << "-" << getMonth() << "-" << getDay();
30 
31 }

account.h

 1 #ifndef __ACCOUNT_H__
 2 #define __ACCOUNT_H__
 3 #include"date.h"
 4 #include<string>
 5 using namespace std;
 6 class SavingsAccount {
 7 private:
 8     string id;
 9     double balance;
10     double rate;
11     Date lastDate;
12     double accumulation;
13     static double total;
14     void record(const Date& date, double amount, const string& desc);
15     void error(const string& msg) const;
16     double accumulate(const Date& date)const {
17         return accumulation + balance * date.distance(lastDate);
18 
19     }
20 public:
21     SavingsAccount(const Date& date, const string& id, double rate);
22     const string& getId()const { return id; }
23     double getBalance()const { return balance; }
24     double getRate()const { return rate; }
25     static double getTotal() { return total; }
26     void deposit(const Date& date, double amount, const string& desc);
27     void withdraw(const Date& date, double amount, const string& desc);
28     void settle(const Date& date);
29     void show() const;
30 
31 };
32 #endif

account.cpp

 1 #include"account.h"
 2 #include<cmath>
 3 #include<iostream>
 4 using namespace std;
 5 double SavingsAccount::total = 0;
 6 SavingsAccount::SavingsAccount(const Date& date, const string& id, double rate) :
 7     id(id), balance(0), rate(rate), lastDate(date), accumulation(0) {
 8     date.show();
 9     cout << "\t#" << id << "created" << endl;
10 }
11 void SavingsAccount::record(const Date& date, double amount, const string& desc) {
12     accumulation = accumulate(date);
13     lastDate = date;
14     amount = floor(amount * 100 + 0.5) / 100;
15     balance += amount;
16     total += amount;
17     date.show();
18     cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;
19 }
20 void SavingsAccount::error(const string& msg) const {
21     cout << "Error(#" << id << "):" << msg << endl;
22 }
23 void SavingsAccount::deposit(const Date& date, double amount, const string& desc) {
24     record(date, amount, desc);
25 }
26 void SavingsAccount::withdraw(const Date& date, double amount, const string& desc) {
27     if (amount > getBalance())
28         error("not enough money");
29     else
30         record(date, -amount, desc);
31 }
32 void SavingsAccount::settle(const Date& date) {
33     double interest = accumulate(date) * rate / date.distance(Date(date.getYear() - 1, 1, 1));
34     if (interest != 0) record(date, interest, "interest");
35     accumulation = 0;
36 }
37 void SavingsAccount::show()const {
38     cout << id << "\tBalance: " << balance;

task6.cpp

 1 #include"account.h"
 2 #include<iostream>
 3 using namespace std;
 4 int main() {
 5     Date date{ 2008,11,1 };
 6     SavingsAccount accounts[] = {
 7         SavingsAccount(date,"03755217",0.015),
 8         SavingsAccount(date,"02342342",0.015)
 9     };
10     const int n = sizeof(accounts) / sizeof(SavingsAccount);
11     accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
12     accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
13     accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
14     accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
15     cout << endl;
16     for (int i = 0; i < n; i++) {
17         accounts[i].settle(Date(2009, 1, 1));
18         accounts[i].show();
19         cout << endl;
20     }
21     cout << "Total: " << SavingsAccount::getTotal() << endl;
22     return 0;
23 }

运行结果截图：

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