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", "[email protected]");
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。