实验任务1：

实验代码：

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

实验截图：

问题1：自定义了两个类，Button和Window；使用了标准库中两个类，string和vector；Button与string有组合关系，Window与string、Button、vector有组合关系。

问题2：Button类中的函数void click()适合设置成inline，该函数较小且简单，并且在实际应用中可能被多次调用。

问题3：生成一个string类对象s，其长度为40，且其中每个字符都为‘*’。

 

实验任务2：

实验代码：

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

实验截图：

问题1：第一行：定义一个int类型的vector数组v1，其长度为5，其中每个数据都为42。

第二行：定义一个int类型的vector数组v2，用v1的值来初始化。

第三行：将v1数组的第一个成员赋值为-999。

问题2：第一行：定义了一个int类型的名为v1的二维vector数组，第一个元素为vector数组{1，2，3}，第二个元素为vector数组{4，5，6，7}。

第二行：定义了一个int类型的名为v2的二维常量vector数组，用v1的值来初始化。

第三行：在二维vector数组v1第一个元素vector数组的末尾添加一个新元素-999。

问题3：第一行：定义一个int类型的vector数组t1，并用二维vector数组v1的第一个元素来初始化。

第二行：输出t1的最后一个元素的值。

第三行：定义了一个int类型的名为t2的常量vector数组，用v2的第一个元素来初始化。

第四行：输出t2的最后一个元素的值。

问题4：深复制；不需要。

 

实验任务3：

实验代码：

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

实验截图：

问题1：深复制。

问题2：可以正确运行。有安全隐患，const有助于保证数据不被意外修改。

问题3：可以改成。返回对象改成vectorInt后每次调用assign()函数会创建一个新的vectorInt对象，性能会降低但不影响实现。

 

实验任务4：

实验代码：

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 Matrix::Matrix(int n, int m): lines{n}, cols{m} {
36     ptr = new double[n*m];
37 }
38 
39 Matrix::Matrix(int n): lines{n}, cols{n} {
40     ptr = new double[n*n];
41 }
42 
43 Matrix::Matrix(const Matrix &x): lines{x.lines}, cols{x.cols} {
44     ptr = new double[lines*cols];
45     for(int i = 0; i < lines*cols; i++) ptr[i] = x.ptr[i];
46 }
47 
48 void Matrix::set(const double *pvalue) {
49     for(int i = 0; i < lines*cols; i++)
50     ptr[i] = pvalue[i];
51 }
52 
53 void Matrix::clear() {
54     for(int i = 0; i < lines*cols; i++)
55     ptr[i] = 0;
56 }
57 
58 const double& Matrix::at(int i, int j) const {
59     assert(i >= 0 && i < lines && j >= 0 && j < cols);
60     return ptr[i*cols + j];
61 }
62 
63 double& Matrix::at(int i, int j) {
64     assert(i >= 0 && i < lines && j >=0 && j < cols);
65     return ptr[i*cols + j];
66 }
67 
68 int Matrix::get_lines() const {
69     return lines;
70 }
71 
72 int Matrix::get_cols() const {
73     return cols;
74 }
75 
76 void Matrix::display() const {
77     for(int i = 0; i < lines; i++) {
78         for(int j = 0; j < cols; j++)
79             cout << ptr[i*cols + j] << ", ";
80         cout << "\n";
81     }
82 }
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

实验截图：

 

实验任务5：

实验代码：

user.hpp:

 1 #pragma once
 2 
 3 #include <iostream>
 4 #include <vector>
 5 #include <string>
 6 
 7 using namespace std;
 8 
 9 class User {
10 public:
11     User(const string& name0, const string& password0 = "123456", const string& email0 = " ");
12     void set_email();
13     void change_password();
14     void display() const;
15 private:
16     string name;
17     string password;
18     string email;
19 };
20 
21 User::User(const string& name0, const string& password0, const string& email0) : name{name0}, password{password0}, email{email0} {}
22 void User::set_email() {
23     string input_email;
24     cout << "Enter email address：";
25     cin >> input_email;
26     while(true) {
27         if(input_email.find('@') != string::npos) {
28         email = input_email;
29         cout << "email is set successfully..." << endl;
30         break; 
31         }
32         else {
33             cout << "illegal email. Please re-enter email：";
34             cin >> input_email; 
35         }
36     }
37 }
38 
39 void User::change_password() {
40     cout << "Enter old password：";
41     string input_password,newpassword;
42     int count = 0;
43     cin >> input_password;
44     while(count < 2) {
45         if(input_password == password) {
46             cout << "Enter new password：";
47             cin >> newpassword;
48             password = newpassword;
49             cout << "new password is set successfully..." << endl;
50             break;  
51         }
52         else {
53             cout << "password input error. Please re-enter again: ";
54             cin >> input_password;
55             count++;
56         }
57     }
58     if(count == 2) {
59         cout << "password input error. Please try after a while." << endl;
60     }
61 }
62 
63 void User::display() const {
64     cout << "用户名：" << name << endl;
65     cout << "密码：" << string(password.length(),'*') << endl;
66     cout << "邮箱：" << email << endl; 
67 }
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

实验截图：

 

实验任务6：

实验代码：

date.h:

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

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 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 
17         + DAYS_BEFIRE_MONTH[month - 1] + day;
18     if (isLeapYear() && month > 2) totalDays++;
19     }
20     int Date::getMaxDay()const {
21         if (isLeapYear() &&month == 2)
22             return 29;
23         else 
24             return DAYS_BEFIRE_MONTH[month] - DAYS_BEFIRE_MONTH[month - 1];
25     }
26     void Date::show()const {
27         cout << getYear() << "-" << getMonth() << "-" << getDay();
28     }
View Code

account.h:

 1 #pragma once
 2 #include "date.h"
 3 #include <string>
 4 class SavingsAccount {
 5 private:
 6     std::string id;
 7     double balance;
 8     double rate;
 9     Date lastDate;
10     double accumulation;
11     static double total;
12     
13     void record(const Date &date, double amount, const std::string &desc);
14     
15     void error(const std::string &msg) const;
16     
17     double accumulate(const Date& date) const {
18         return accumulation+balance*date.distance(lastDate);
19     }
20 public:
21     SavingsAccount(const Date &date, const std::string &id, double rate);
22     const std::string &getId() const {return id;}
23     double getBalance() const {return balance;}
24     double getRate() const {return rate;}
25     static double getTotal() {return total;}
26     
27     void deposit(const Date &date, double amount, const std::string &desc);
28     
29     void withdraw(const Date &date, double amount, const std::string &desc);
30     
31     void settle(const Date &date);
32     
33     void show() const;
34 };
View Code

account.cpp:

 1 #include "account.h"
 2 #include <cmath>
 3 #include <iostream>
 4 using namespace std;
 5 double SavingsAccount::total = 0;
 6 
 7 SavingsAccount::SavingsAccount(const Date &date, const string &id, double rate)
 8     : id(id), balance(0), rate(rate), lastDate(date), accumulation(0) {
 9         date.show();
10         cout << "\t#" << id << "created" << endl;
11     }
12 
13 void SavingsAccount::record (const Date &date, double amount, const string &desc) {
14     accumulation = accumulate(date);
15     lastDate = date;
16     amount = floor(amount*100 + 0.5)/100;
17     balance += amount;
18     total += amount;
19     date.show();
20     cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;
21 }
22 
23 void SavingsAccount::error(const string &msg) const {
24     cout << "Error(#"<<id<<"): " << msg << endl;
25 }
26 
27 void SavingsAccount::deposit(const Date &date, double amount, const string &desc) {
28     record(date, amount, desc);
29 }
30 
31 void SavingsAccount::withdraw(const Date &date, double amount, const string &desc) {
32     if(amount > getBalance())
33         error("not enough money");
34     else
35         record(date, -amount, desc);
36 }
37 
38 void SavingsAccount::settle(const Date &date) {
39     double interest = accumulate(date)*rate
40         / date.distance(Date(date.getYear()-1, 1, 1));
41     if(interest != 0)
42         record(date, interest, "interest");
43     accumulation = 0;
44 }
45 
46 void SavingsAccount::show() const {
47     cout << id << "\tBalance: " << balance;
48 }
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 
14     accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
15     accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
16 
17     cout << endl;
18     for (int i = 0; i < n; i++) {
19         accounts[i].settle(Date(2009, 1, 1));
20         accounts[i].show();
21         cout << endl;
22     }
23     cout << "Total: " << SavingsAccount::getTotal() << endl;
24     return 0;
25 }
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实验截图：

上面的程序增加了Date类，把对日期的表示均替换成了Date类型，输出效果比原来相比要直观的多。此外，本例广泛应用了字符串，这样在银行账号中可以出现字母，而且为每笔账目增加了说明文字，使得程序输出的信息更加丰富。