实验三类和对象

任务一：

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 }

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

运行截图：

问题一：自定义了两个类button和window，使用了标准库的std::string,std::vector,std::iostream;window类中包含了一个std::vector<button>类型的成员变量buttons，wintow和button之间存在组合关系

问题二：不合适，const不修改对象的值，没有添加const的对象会修改对象的值，inline适合简单的函数，且使用频率较高，适合内联，其他的都不适合内联。

问题三：这是一个字符串，长度为40，均为*

任务二：

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

问题一：第一行创建一个名为v1的vector<int>对象，该对象包含5个元素每个元素都被初始化为42；第二行创建v2对象，它是通过复制v1来初始化的；第三行是把v1中的第一个元素修改为-999；

问题二：第一行创建名为v1的二维向量，包含两个子向量，第一个含元素{1,2,3}第二个含{4,5,6,7}；第二行名为v2的const二维向量，是通过复制v1来初始化的；第三行是v1中第一个元素添加-999；

问题三：第一行将v1中第一个量赋值给t1；第二行输出t1的最后一个元素；第三行把v2中第一个量赋值给新的对象t2；第四行输出t2的最后一个元素

问题四：深复制；不需要

任务三：

代码：

vectorlnt.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

运行截图：

问题1：深复制，因为重新用new函数动态分配了一块空间，地址不共享

问题2：不是int &的话，那么数组的值就不能改变了，不能正常运行；18行中的consts删去有隐患，虽然对象x是const类型，已经不能修改x中的数据成员，但只是指针和元素个数size不能改变，数组中的值依旧可以改变，为了确保数组中的值不能被改变，必须设为const int &类型

问题3：可以，程序正常运行（感觉就是返回值为引用类型的话，就不用再调用一次复制构造函数了），返回值不是引用类型的话，就相当于assign之后又把那个初始化后的对象又用复制构造函数复制给了另一个新对象

任务四：

代码：

matrix：

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

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 }

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运行截图：

实验五：

代码：

user：

 1 #pragma once
 2 
 3 #include <iostream>
 4 #include <cassert>
 5 #include<string>
 6 
 7 using std::cout;
 8 using std::endl;
 9 class User{
10     private:
11         string name;
12         string password;
13         string email;
14     public:
15         User (string a){
16         name=a;
17         password=123456;
18         email=NULL;        
19         }
20         User(string a,string b,string c){
21             name=a;
22             password=b;
23             email=c;
24         }
25     User::set_email(){
26         string a;
27         std::cout<<"Enter email adress";
28         std::cout<<endl;
29         std::cin>> a ;
30         if(a.find('@')!=-1 ){
31             std::cout<<"email is set successfully...";
32             email=a;
33             break;
34         }else{
35             std::cout<<"illegal email.please re-enter email";
36                 
37         }
38     }
39     User::change_password(){
40         string b;
41         std::cout<<"Enter old password";
42         std::cin>> b;
43             if(b==password){
44                 break;
45             }else{
46                 std::cout<<"password input error.Please re-enter again:    ";        
47                 std::cin>>b;
48                 }if(b==password){
49                     break;
50                 }else{
51                        std::cout<<"password input error.Please re-enter again:"    ;                  
52                        std::cin>>b;                                
53                        }if(b!=password){
54                             std::cout<<"password input error.Please try after a while";
55                        }
56             
57     User::display(){
58         stirng c(password.size(),"*") 
59         std::cout<<"email:  "<<email<<endl;
60         std::cout<<"password:   "<<c<<endl;
61         std::cout<<"name:  "<<name<<endl;        
62     }    
63     
64     
65 };

View Code

task5：

 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 }

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运行截图：

实验六

代码：

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

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
17     + DAYS_BEFORE_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_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];
25 }
26 void Date::show() const {
27      cout << getYear() << "-" << getMonth() << "-" << getDay();
28 }

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   
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   
22     SavingsAccount(const Date & date, const std::string & id, double rate);
23     const std::string & getId() const { return id; }
24     double getBalance() const { return balance; }
25     double getRate() const { return rate; }
26     static double getTotal() { return total; }
27    
28     void deposit(const Date & date, double amount, const std::string & desc);
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 };
35 #endif

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 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 void SavingsAccount::error(const string & msg) const {
22     cout << "Error(#" << id << "): " << msg << endl;
23 }
24 void SavingsAccount::deposit(const Date & date, double amount, const string & desc) {
25     record(date, amount, desc);
26 }
27 void SavingsAccount::withdraw(const Date & date, double amount, const string & desc) {
28     if (amount > getBalance())
29         error("not enough money");
30     else
31         record(date, -amount, desc);
32 }
33 void SavingsAccount::settle(const Date & date) {
34     double interest = accumulate(date) * rate    
35         / date.distance(Date(date.getYear() - 1, 1, 1));
36     if (interest != 0)
37         record(date, interest, "interest");
38     accumulation = 0;
39 }
40 void SavingsAccount::show() const {
41     cout << id << "\tBalance: " << balance;
42 }

View Code

task6.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),
 9         SavingsAccount(date, "02342342", 0.015)
10     };
11     const int n = sizeof(accounts) / sizeof(SavingsAccount); 
12   
13     accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
14     accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
15    
16     accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
17     accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
18 
19     cout << endl;
20     for (int i = 0; i < n; i++) {
21         accounts[i].settle(Date(2009, 1, 1));
22         accounts[i].show();
23         cout << endl;
24     }
25     cout << "Total: " << SavingsAccount::getTotal() << endl;
26     return 0;
27 }

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posted @ 2024-11-11 13:56 白鸽nm海鸥阅读(2) 评论(0) 编辑收藏举报

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实验三 类和对象

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实验三类和对象