实验3 类和对象_基础编程2

实验一：

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 }

windows.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1：自定义了两个类，用了标准库的vector类；window类包含vector数组，数组元素类型为button对象。

问题2：不适合，const是为了保证数据不被修改，而inline是为了让函数内联，加快程序运行速度。

问题3：定义一个字符串s,其内容为40个*。

实验二：

代码：

 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：

问题1：第一行是构造vector数组v1，类型为整型，初始有5个元素，每个元素都是42；第二行是构造vector数组v2，类型为整型，内容复制v1；第三行是用vector数组的at（）函数，索引vector数组0号位置的元素，将其改为-999。

问题2：第一行是构造vector数组v1，类型为vector整型数组类型，第一个vector数组元素赋值为1，2，3。第二个vector数组元素赋值为4，5，6，7;第二行是构造vector数组v2，类型为vector整型数组类型，内容复制v1，并且不可以修改；第三行是索引v1数组0号元素，将-999插入末尾。

问题3：第一行是构造vector整型数组t1，内容为v1数组的首个元素；第二行是输出t1的末尾元素并换行；第三行是构造vector整型数组t2，内容为v2的首个元素，并且不可以修改；第四行是输出t2的末尾元素并换行。

问题4：（1）深复制，因为改变被复制对象的元素，复制对象的元素不会跟着改变。

(2)需要，因为有时使用at不需要改变其值，只需要输出值，此时用const成员函数可以保证值不会被改变。

实验三：

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 }

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 }

运行结果：

问题1：深复制。

问题2：不能，因为&代表引用，返回值引用原来的对象的成员，如果修改对象的成员也会跟着改变，达到目的，如果去掉就无法成功改变值。const去掉会有安全隐患，因为const表明他的返回值是const int类型，不能修改。

问题3：不能，因为返回值是引用被复制后的vectorInt对象，是原来的被改变的对象，如果去掉就返回一个新的复制的对象。会占用多于内存。

实验四：

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 class Matrix {
10 public:
11     Matrix(int n, int m);
12     Matrix(int n);
13     Matrix(const Matrix& x);
14     ~Matrix();
15 
16     void set(const double* pvalue);
17     void clear();
18 
19     const double& at(int i, int j)const;
20     double& at(int i, int j);
21 
22     int get_lines()const;
23     int get_cols()const;
24 
25     void display()const;
26 
27 private:
28     int lines;
29     int cols;
30     double* ptr;
31 };
32 
33 Matrix::Matrix(int n, int m) :lines{ n }, cols{ m } {
34     ptr = new double [n*m];
35 }
36 
37 Matrix::Matrix(int n) :lines{ n }, cols{ n } {
38     ptr = new double[n * n];
39 }
40 
41 Matrix::Matrix(const Matrix& x) {
42     lines = x.lines;
43     cols = x.cols;
44     ptr = new double[lines * cols];
45     for (int i = 0; i < lines * cols; i++)
46         ptr[i] = x.ptr[i];
47 }
48 
49 Matrix::~Matrix() {
50     delete[]ptr;
51 }
52 
53 void Matrix::set(const double* pvalue) {
54     for (int i = 0; i < lines * cols; i++) {
55         ptr[i] = pvalue[i];
56     }
57 }
58 
59 void Matrix::clear() {
60     for (int i = 0; i < lines * cols; i++) {
61         ptr[i] = 0;
62     }
63 }
64 
65 const double& Matrix::at(int i, int j)const {
66     return ptr[i  * cols + j];
67 }
68 
69 double& Matrix::at(int i, int j) {
70     return ptr[i  * cols + j];
71 }
72 
73 int Matrix::get_lines()const {
74     return lines;
75 }
76 
77 int Matrix::get_cols()const {
78     return cols;
79 }
80 
81 void Matrix::display()const {
82     for (int i = 0; i < lines * cols; i++) {
83         if ((i + 1) % cols != 0)
84             cout << ptr[i] << " ,";
85         else
86             cout << ptr[i] << endl;
87     }
88 }

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 const int N = 1000;
10 
11 void output(const Matrix& m, int index) {
12     assert(index >= 0 && index < m.get_lines());
13 
14     for (auto j = 0; j < m.get_cols(); j++)
15         cout << m.at(index, j) << ",";
16     cout << "\b\b\n";
17 }
18 
19 void test1() {
20     double x[1000] = { 5,6,7,8,9,10,11,12,13,14 };
21     
22     int n, m;
23     cout << "Enter n and m:";
24     cin >> n >> m;
25 
26     Matrix m1(n, m);
27     m1.set(x);
28 
29     Matrix m2(m, n);
30     m2.set(x);
31 
32     Matrix m3(2);
33     m3.set(x);
34 
35     cout << "矩阵对象m1:\n"; m1.display(); cout << endl;
36     cout << "矩阵对象m2:\n"; m2.display(); cout << endl;
37     cout << "矩阵对象m3:\n"; m3.display(); cout << endl;
38 }
39 
40 void test2() {
41     Matrix m1(2, 3);
42     m1.clear();
43 
44     const Matrix m2(m1);
45     m1.at(0, 0) = -999;
46 
47     cout << "m1.at(0,0)=" << m1.at(0, 0) << endl;
48     cout << "m2.at(0,0)=" << m2.at(0, 0) << endl;
49     cout << "矩阵对象m1第0行："; output(m1, 0);
50     cout << "矩阵对象m2第0行："; output(m2, 0);
51 }
52 
53 int main() {
54     cout << "测试1：\n";
55     test1();
56 
57     cout << "测试2：\n";
58     test2();
59 }

运行结果：

实验五：

代码：

user.hpp:

 1 #pragma once
 2 #include<iostream>
 3 #include<string>
 4 
 5 using namespace std;
 6 
 7 class User {
 8 public:
 9     User(string n) :name{ n } {
10         password = "123456";
11         email = " ";
12     }
13     User(string n, string p, string e) :name{ n }, password{ p }, email{ e } {
14     }
15 
16     void set_email() {
17         int judge = 0;                
18         string e;
19         cout << "请输入邮箱：";
20         while(judge!=1){
21             cin >> e;
22             for (char i : e) {
23                 if (i == '@') {
24                    judge = 1;
25                    break;
26                 }    
27             }
28             if (judge == 1)break;
29             else 
30                 cout << "不是合法邮箱，请重新输入：";
31         }
32         email = e;
33         cout << "邮箱设置成功"<<endl;
34     }
35 
36     void change_password() {
37         int times=0;
38         string oldp,newp;
39         cout << "输入旧密码：";
40         do {
41             cin >> oldp;
42             if (oldp == password)
43                 break;
44             else times++;
45             cout << "密码错误，请重新输入密码：";
46             if (times == 3) {
47                 cout << "连续三次输入错误，请稍后再试" << endl;
48                 return;
49             }
50         } while (true);
51         cout << "请输入新密码：";
52         cin >> newp;
53         password = newp;
54         cout << "新密码设置成功" << endl;
55     }
56 
57     void display() {
58         int length = 0;
59         length = password.size();
60         string protection(length, '*');
61         cout << "name:  " << name << endl;
62         cout << "pass:  " << protection << endl;
63         cout << "email:  " << email << endl;
64         cout << endl;
65     }
66 private:
67     string name, password, email;
68 };

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_1st;
14 
15     User u1("Alice", "2024113", "Alice@hotmail.com");
16     user_1st.push_back(u1);
17     cout << endl;
18 
19     User u2("Bob");
20     u2.set_email();
21     u2.change_password();
22     user_1st.push_back(u2);
23     cout << endl;
24 
25     User u3("Hellen");
26     u3.set_email();
27     u3.change_password();
28     user_1st.push_back(u3);
29     cout << endl;
30 
31     cout << "There are" << user_1st.size() << "users.they are::" << endl;
32     for (auto& i : user_1st) {
33         i.display();
34         cout << endl;
35     }
36 }
37 
38 int main() {
39     test();
40 }

运行结果：

实验六：

代码：

date.h:

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

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 int Date::getMaxDay()const {
20     if (isLeapYear() && month == 2)
21         return 29;
22     else
23         return DAYS_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];
24 }
25 void Date::show()const {
26     cout << getYear() << "-" << getMonth() << "-" << getDay();
27 }

account.h:

 1 #pragma once
 2 #ifndef  ACCOUNT H
 3 #define  ACCOUNT H
 4 #include"date.h"
 5 #include<string>
 6 class SavingsAccount {
 7 private:
 8     std::string id;
 9     double balance;
10     double rate;
11     Date lastDate;
12     double accumulation;
13     static double total;
14 
15     void record(const Date& date, double amount, const std::string& desc);
16 
17     void error(const std::string& msg)const;
18 
19     double accumulate(const Date& date)const {
20         return accumulation + balance * date.distance(lastDate);
21     }
22 public:
23     SavingsAccount(const Date& date, const std::string& id, double rate);
24     const std::string& getId()const { return id; }
25     double getBalance()const { return balance; }
26     double getRate()const { return rate; }
27     static double getTotal() { return total; }
28 
29     void deposit(const Date& date, double amount, const std::string& desc);
30 
31     void withdraw(const Date& date, double amount, const std::string& desc);
32 
33     void settle(const Date& date);
34 
35     void show()const;
36 };
37 #endif//  ACCOUNT H

account.cpp:

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

6_25.cpp:

 1 #include"account.h"
 2 #include<iostream>
 3 using namespace std;
 4 int main() {
 5     Date date(2008, 11, 1);
 6 
 7     SavingsAccount accounts[] = {
 8         SavingsAccount(date,"03755217",0.015),SavingsAccount(date,"02342342",0.015)
 9     };
10     const int n = sizeof(accounts) / sizeof(SavingsAccount);
11 
12     accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
13     accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
14 
15     accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
16     accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
17 
18     cout << endl;
19     for (int i = 0; i < n; i++) {
20         accounts[i].settle(Date(2009, 1, 1));
21         accounts[i].show();
22         cout << endl;
23     }
24     cout << "Total:" << SavingsAccount::getTotal() << endl;
25     return 0;
26 }

运行结果：

posted @ 2024-11-05 19:49 霍学金阅读(12) 评论(0) 编辑收藏举报

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实验3 类和对象_基础编程2

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