实验3 类和对象_基础编程2

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 }

View Code

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 }

View Code

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 }

View Code

运行结果

问题1：自定义了两个类：button和window；用到了标准库的string类和vector类；buttion类和vector类存在组合关系(vector<Button>)。

问题2：不适合；const修饰的函数不会改变对象的成员，inline适合修饰代码量小且调用次数多的函数。

问题3：美化运行窗口，增强终端可读性和易用性

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 }

View Code

运行结果

问题1：为整型容器v1初始化5个值为42的元素;将v1的元素拷贝给v2;将v1中索引为0的元素设为-999。

问题2：定义一个容器v1，装着两个整型容器，并初始化这两个整行容器，使其元素分别为1,2,3和4,5,6,7;

定义一个const型的整数容器的容器，将v1的元素拷贝给它；

在v1中索引为0的整数容器中加入一个新元素-999。

问题3：定义一个整数容器t1,将v1中索引为0的容器的元素赋给它；

输出t1中最后一个元素并换行；

定义一个const型的整数容器t2，将v2中索引为0的容器的元素赋给它；

输出t2中最后一个元素并换行；

问题4：（1）深复制

（2）是，因为使用接口的对象可能为const类型。

任务3

vectorInt.hpp

 1 #pragma once
 2 
 3 #include <iostream>
 4 #include <cassert>
 5 
 6 using std::cout;
 7 using std::endl;
 8 
 9 // 动态int数组对象类
10 class vectorInt{
11 public:
12     vectorInt(int n);
13     vectorInt(int n, int value);
14     vectorInt(const vectorInt &vi);
15     ~vectorInt();
16 
17     int& at(int index);
18     const int& at(int index) const;
19 
20     vectorInt& assign(const vectorInt &v);
21     int get_size() const;
22 
23 private:
24     int size;
25     int *ptr;       // ptr指向包含size个int的数组
26 };
27 
28 vectorInt::vectorInt(int n): size{n}, ptr{new int[size]} {
29 }
30 
31 vectorInt::vectorInt(int n, int value): size{n}, ptr{new int[size]} {
32     for(auto i = 0; i < size; ++i)
33         ptr[i] = value;
34 }
35 
36 vectorInt::vectorInt(const vectorInt &vi): size{vi.size}, ptr{new int[size]} {
37     for(auto i = 0; i < size; ++i)
38         ptr[i] = vi.ptr[i];
39 }
40 
41 vectorInt::~vectorInt() {
42     delete [] ptr;
43 }
44 
45 const int& vectorInt::at(int index) const {
46     assert(index >= 0 && index < size);
47 
48     return ptr[index];
49 }
50 
51 int& vectorInt::at(int index) {
52     assert(index >= 0 && index < size);
53 
54     return ptr[index];
55 }
56 
57 vectorInt& vectorInt::assign(const vectorInt &v) {  
58     delete[] ptr;       // 释放对象中ptr原来指向的资源
59 
60     size = v.size;
61     ptr = new int[size];
62 
63     for(int i = 0; i < size; ++i)
64         ptr[i] = v.ptr[i];
65 
66     return *this;
67 }
68 
69 int vectorInt::get_size() const {
70     return size;
71 }

View Code

task3.cpp

 1 #include "vectorInt.hpp"
 2 #include <iostream>
 3 
 4 using std::cin;
 5 using std::cout;
 6 
 7 void output(const vectorInt &vi) {
 8     for(auto i = 0; i < vi.get_size(); ++i)
 9         cout << vi.at(i) << ", ";
10     cout << "\b\b \n";
11 }
12 
13 
14 void test1() {
15     int n;
16     cout << "Enter n: ";
17     cin >> n;
18 
19     vectorInt x1(n);
20     for(auto i = 0; i < n; ++i)
21         x1.at(i) = i*i;
22     cout << "x1: ";  output(x1);
23 
24     vectorInt x2(n, 42);
25     vectorInt x3(x2);
26     x2.at(0) = -999;
27     cout << "x2: ";  output(x2);
28     cout << "x3: ";  output(x3);
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 }

View Code

运行结果

问题1：深复制

问题2：不能运行，报错如下：

因为只有返回引用类型的函数才能在调用时进行左值运算。

如果把line18返回值类型前面的const掉，针对这个测试代码，有潜在安全隐患。如果去掉const，at()返回的引用类型可能会被错误地改变。

问题3：当函数返回引用类型时，返回的是对象本身，没有复制的操作。如果改为vectorint，会导致返回值的拷贝，可能会降低性能。

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 // 类Matrix的实现：待补足
35 // xxx

View Code

matrix.cpp

 1 #include "matrix.hpp"
 2 #include<iostream>
 3 #include <cstring> 
 4 using namespace std;
 5 
 6 Matrix::Matrix(int n, int m):lines(n),cols(m) {
 7     ptr = new double[n * m]; 
 8 }
 9 
10 Matrix::Matrix(int n) : Matrix(n, n) {}
11 
12 Matrix::Matrix(const Matrix &x):lines(x.lines),cols(x.cols) {
13     ptr = new double[lines * cols];  
14     memcpy(ptr, x.ptr, sizeof(double) * lines * cols);
15 }
16 
17 Matrix::~Matrix() {
18     delete[] ptr;
19 }
20 
21 void Matrix::set(const double *pvalue)
22 {
23     memcpy(ptr, pvalue, sizeof(double) * lines * cols);
24 }
25 
26 void Matrix::clear()
27 {
28     memset(ptr, 0, sizeof(double) * lines * cols); 
29 }
30 
31 const double& Matrix::at(int i, int j) const 
32 {
33     return ptr[i * cols + j];
34 } 
35 
36 double& Matrix::at(int i, int j) 
37 {
38     return ptr[i * cols + j];
39 }   
40 
41 int Matrix::get_lines() const
42 {
43     return lines;
44 }  
45 
46 int Matrix::get_cols() const
47 {
48     return cols;
49 }    
50 
51 void Matrix::display() const
52 {
53     for (int i = 0; i < lines; i++) 
54     {  
55         for (int j = 0; j < cols; j++) 
56         {  
57             std::cout << at(i, j) << " "; 
58         }  
59             std::cout << std::endl;  
60     }  
61 }
62     
63

View Code

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 }

View Code

将test1中代码改为double x[1000] = {4, 5, 6, 1, 2, 3, 7, 8, 9};后运行结果为

任务5

user.hpp

  1 #ifndef USER_HPP  
  2 #define USER_HPP  
  3 
  4 #include <iostream>  
  5 #include <vector>  
  6 #include <string>  
  7 
  8 class User {  
  9 private:  
 10     std::string name;  
 11     std::string password;  
 12     std::string email;  
 13 
 14     void input_email() {  
 15         while (true) {  
 16             std::cout << "请输入邮箱地址: ";  
 17             std::string input_email;  
 18             std::cin >> input_email;  
 19             if (input_email.find('@') != std::string::npos) { //如果输入的邮箱中有@ 
 20                 email = input_email;  
 21                 std::cout << "设置成功！\n"; 
 22                 break;  
 23             } else {  
 24                 std::cout << "邮箱格式不合法，请重新输入。\n";  
 25             }  
 26         }  
 27     }  
 28 
 29 public:  
 30     // 只输入名字时，默认密码为“123456”，邮箱为空  
 31     User(const std::string& name) : name(name), password("123456"), email("") {}  
 32 
 33     // 自定义构造函数  
 34     User(const std::string& name, const std::string& password, const std::string& email)  
 35         : name(name), password(password), email(email) {}  
 36 
 37     void set_email() {  //设置邮箱  
 38         input_email();  
 39     }  
 40 
 41     void change_password() {   //修改密码 
 42         std::string old_password;  
 43         int attempts = 0;  //尝试次数（3） 
 44         while (attempts < 3) {  
 45             std::cout << "请输入旧密码: ";  
 46             std::cin >> old_password;  
 47             if (old_password == password) {   //验证成功 
 48                 std::cout << "请输入新密码: ";  
 49                 std::string new_password;  
 50                 std::cin >> new_password;  
 51                 password = new_password;  
 52                 std::cout << "密码修改成功。\n";  
 53                 return;  
 54             } else {  //验证失败 
 55                 std::cout << "旧密码错误，请重试。\n";  
 56                 attempts++;  
 57             }  
 58         }  
 59         std::cout << "多次输入错误，请稍后再试。\n";  
 60     }  
 61 
 62     void display() const {  //展示（密码隐藏） 
 63         std::cout << "用户名: " << name << "\n";  
 64         std::cout << "密码: " << std::string(password.size(), '*') << "\n";  
 65         std::cout << "邮箱: " << email << "\n";  
 66     }  
 67 };  
 68 
 69 #endif // USER_HPP  #ifndef USER_HPP  
 70 #define USER_HPP  
 71 
 72 #include <iostream>  
 73 #include <vector>  
 74 #include <string>  
 75 
 76 class User {  
 77 private:  
 78     std::string name;  
 79     std::string password;  
 80     std::string email;  
 81 
 82     void input_email() {  
 83         while (true) {  
 84             std::cout << "请输入邮箱地址: ";  
 85             std::string input_email;  
 86             std::cin >> input_email;  
 87             if (input_email.find('@') != std::string::npos) { //如果输入的邮箱中有@ 
 88                 email = input_email;  
 89                 std::cout << "设置成功！\n"; 
 90                 break;  
 91             } else {  
 92                 std::cout << "邮箱格式不合法，请重新输入。\n";  
 93             }  
 94         }  
 95     }  
 96 
 97 public:  
 98     // 只输入名字时，默认密码为“123456”，邮箱为空  
 99     User(const std::string& name) : name(name), password("123456"), email("") {}  
100 
101     // 自定义构造函数  
102     User(const std::string& name, const std::string& password, const std::string& email)  
103         : name(name), password(password), email(email) {}  
104 
105     void set_email() {  //设置邮箱  
106         input_email();  
107     }  
108 
109     void change_password() {   //修改密码 
110         std::string old_password;  
111         int attempts = 0;  //尝试次数（3） 
112         while (attempts < 3) {  
113             std::cout << "请输入旧密码: ";  
114             std::cin >> old_password;  
115             if (old_password == password) {   //验证成功 
116                 std::cout << "请输入新密码: ";  
117                 std::string new_password;  
118                 std::cin >> new_password;  
119                 password = new_password;  
120                 std::cout << "密码修改成功。\n";  
121                 return;  
122             } else {  //验证失败 
123                 std::cout << "旧密码错误，请重试。\n";  
124                 attempts++;  
125             }  
126         }  
127         std::cout << "多次输入错误，请稍后再试。\n";  
128     }  
129 
130     void display() const {  //展示（密码隐藏） 
131         std::cout << "用户名: " << name << "\n";  
132         std::cout << "密码: " << std::string(password.size(), '*') << "\n";  
133         std::cout << "邮箱: " << email << "\n";  
134     }  
135 };  
136 
137 #endif // USER_HPP

View Code

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 }

View Code

运行结果

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         void show() const;
19         
20         int distance(const Date& date) const {
21             return totalDays-date.totalDays;
22         }
23 };
24 #endif //__DATE_H__

View Code

date.cpp

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

View Code

account.h

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

View Code

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):id(id),balance(0),rate(rate),lastDate(date),accumulation(0) {
 7     date.show();
 8     cout<<"\t#"<<id<<" created"<<endl;
 9 }
10 void SavingsAccount::record(const Date &date,double amount,const std::string &desc) {
11     accumulation=accumulate(date);
12     lastDate=date;
13     amount=floor(amount*100+0.5)/100;
14     balance+=amount;
15     total+=amount;
16     date.show();
17     cout<<"\t#"<<id<<"\t"<<amount<<"\t"<<balance<<"\t"<<desc<<endl;
18 }
19 void SavingsAccount::error(const string &msg) const {
20     cout<<"Error(#"<<id<<":"<<msg<<endl;
21 }
22 void SavingsAccount::deposit(const Date &date,double amount,const string &desc) {
23     record(date,amount,desc);
24 }
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 
33 void SavingsAccount::settle(const Date &date) {
34     double interest=accumulate(date) * rate/date.distance(Date(date.getYear()-1,1,1));
35     if(interest!=0)
36         record(date,interest,"interest");
37     accumulation=0;
38 }
39 void SavingsAccount::show() const{
40     cout<<id<<"\tBalance:"<<balance;
41 }

View Code

6_25.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 }

View Code

运行结果

改进建议：

尽量使用this指针来表示当前对象，避免混淆。
在处理金钱方面，可以考虑引入一个更加稳健的金钱处理类，避免浮点数精度带来的问题。
可以考虑使用异常处理来处理错误，而不是简单地打印错误消息。
可以考虑在show函数中添加更多信息，如账户创建日期、利率等，提供更全面的账户状态信息。
如果函数不修改类的成员变量，应该将其声明为常量成员函数（使用const）。例如，getBalance()、getId()等函数如果只是读取值，则应声明为 const。
保持代码风格的一致性，比如在函数定义和参数之间的空白、括号的使用、控制流的结构等。

posted @ 2024-11-05 15:37 shorekeeper 阅读(5) 评论(0) 编辑收藏举报

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