实验3 类和对象_基础编程2

1.实验任务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 &test);
13         string get_label() const;
14         void click();
15         
16     private:
17         string label;
18 };
19 
20 Button::Button(const string &test):label{test} {}
21 
22 inline string Button::get_label() const{
23     return label;
24 }
25 
26 void Button::click(){
27     cout<<"Button '"<<label<<"' clicked\n";
28 }

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 }

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 }

结果截图：

Q1：自定义了Button类和window类，使用标准库中的std::cout、std::vector、std::string

　　 window类包含vector<Button> buttons，window类和Button类存在组合关系

　　 buttons.push_back()、buttons.size()，Button类和vector类存在组合关系

Q2：Button类中，click()不适合加const，因为输出时改变状态，不是常量

　　 window类中，close()不适合加const，因为它调用了click()，不是常量

　　 window类中，display()适合加inline，因为函数较简单

Q3：创建一个名为s的字符串对象，内容为40个“*”，起到分隔线的作用，利于用户阅读

2.实验任务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<<"\n测试1:\n";
48     test1();
49     cout<<"\n测试2:\n";
50     test2();
51 }

结果截图：

Q1：vector<int> v1(5,42); //创建一个名为v1的vector对象，共5个元素，每个元素为42，即v1={42,42,42,42,42}

　　 const vector<int> v2(v1); //创建一个名为v2的vector对象，为常量，将v1的内容拷贝给v2，即v2={42,42,42,42,42}

　　 v1.at(0)=-999; //将v1中第一个元素更改为-999，即v1={-999,42,42,42,42}

Q2：vector<vector<int>> v1{{1,2,3},{4,5,6,7}}; //创建一个名为v1的二维vector对象，即v1={{1,2,3},{4,5,6,7}}

　　 const vector<vector<int>> v2(v1); ////创建一个名为v2的二维vector对象，为常量，将v1的内容拷贝给v2，即v2={{1,2,3},{4,5,6,7}}

　　 v1.at(0).push_back(-999); //在v1第一个向量中添加元素-999，即v1={{1,2,3,-999},{4,5,6,7}}

Q3：vector<int> t1=v1.at(0); //将v1第一个向量赋值给一维向量t1，即t1={1,2,3,-999}

　　 cout<<t1.at(t1.size()-1)<<endl; //输出向量t1中最后一个元素，即-999

　　 const vector<int> t2=v2.at(0); //将v2第一个向量赋值给一维向量t2，即t2={1,2,3}

　　 cout<<t2.at(t2.size()-1)<<endl; //输出向量t2中最后一个元素，即3

Q4：1）深复制

　　 2）需要

3.实验任务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 vectorInt::vectorInt(int n,int value):size{n},ptr{new int[size]}{
31     for(auto i=0;i<size;++i)
32         ptr[i]=value;
33 } 
34 
35 vectorInt::vectorInt(const vectorInt &vi):size{vi.size},ptr{new int[size]}{
36     for(auto i=0;i<size;++i)
37         ptr[i]=vi.ptr[i];
38 }
39 
40 vectorInt::~vectorInt(){
41     delete [] ptr;
42 }
43 
44 const int& vectorInt::at(int index) const {
45     assert(index>=0&&index<size);
46     
47     return ptr[index];
48 }
49 
50 int& vectorInt::at(int index){
51     assert(index>=0&&index<size);
52     
53     return ptr[index];
54 }
55 
56 vectorInt& vectorInt::assign(const vectorInt &v){
57     delete[] ptr; //释放对象中ptr原来指向的资源
58     
59     size=v.size;
60     ptr=new int[size];
61     
62     for(int i=0;i<size;++i)
63         ptr[i]=v.ptr[i];
64         
65     return *this;
66 }
67 
68 int vectorInt::get_size() const{
69     return size;
70 }

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 void test1(){
14     int n;
15     cout<<"Enter n: ";
16     cin>>n;
17     
18     vectorInt x1(n);
19     for(auto i=0;i<n;++i)
20         x1.at(i)=i*i;
21     cout<<"x1: "; output(x1);
22     
23     vectorInt x2(n,42);
24     vectorInt x3(x2);
25     x2.at(0)=-999;
26     cout<<"x2: "; output(x2);
27     cout<<"x3: "; output(x3); 
28 }
29 
30 void test2(){
31     const vectorInt x(5,42);
32     vectorInt y(10,0);
33     
34     cout<<"y: "; output(y);
35     y.assign(x);
36     cout<<"y: "; output(y);
37     
38     cout<<"x.at(0)= "<<x.at(0)<<endl;
39     cout<<"y.at(0)= "<<y.at(0)<<endl;
40 }
41 
42 int main() {
43     cout << "测试1: \n";
44     test1();
45     cout << "\n测试2: \n";
46     test2();
47 }

结果截图：

Q1：深复制

Q2：能

　　有安全隐患，const vectorInt x(5,42);执行时调用可能会修改元素的值

Q3：可以，但如果改成vectorInt，每次调用 assign() 时都要创建一个新对象来拷贝，会占据额外内存空间

4.实验任务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
35 Matrix::Matrix(int n, int m):lines(n),cols(m),ptr{new double[lines*cols]}{
36 }
37 
38 Matrix::Matrix(int n):Matrix(n,n){
39 }
40 
41 Matrix::Matrix(const Matrix &x):lines{x.lines},cols{x.cols},ptr{new double[lines*cols]}{
42     for(auto i=0;i<lines*cols;i++){
43             ptr[i]=x.ptr[i];
44         }
45 }
46 
47 Matrix::~Matrix(){
48     delete []ptr;
49 }
50 
51 void Matrix::set(const double *pvalue){
52     for(auto i=0;i<lines*cols;i++)
53             ptr[i]=pvalue[i];
54 }
55 
56 void Matrix::clear(){
57     for(auto i=0;i<lines*cols;i++)
58             ptr[i]=0;
59 }
60 
61 const double& Matrix::at(int i, int j) const{
62     assert(i>=0&&i<lines&&j>=0&&j<cols);
63     
64     return ptr[i*cols+j];
65 }
66 
67 double& Matrix::at(int i, int j){
68     assert(i>=0&&i<lines&&j>=0&&j<cols);
69     
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;i++){
83         for(int j=0;j<cols;j++)
84             cout<<ptr[i*cols+j];
85         cout<<endl;
86     }
87 }

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 }

结果截图：

5.实验任务5

user.hpp

 1 #pragma once
 2 #include<iostream>
 3 #include <string>
 4 #include <vector>
 5 
 6 using namespace std;
 7 
 8 class User{
 9     public:
10         User(string a,string b="123456",string c=" ");
11         
12         void set_email();
13         void change_password();
14         void display() const;
15         
16     private:
17         string name,password,email;    
18 };
19 
20 User::User(string a,string b,string c):name(a),password(b),email(c){}
21 
22 void User::set_email(){
23     string c;
24     cout<<"Enter email address: ";
25     while(cin>>c){
26         vector<string> v{c};
27         for(auto &c:v){
28             auto pos=c.find("@");
29             if(pos==string::npos){
30                 cout<<"illegal email. Please re-enter email: ";
31             }
32             else{
33                 cout<<"email is set successfully..."<<endl;
34                 email=c;
35                 break;
36             }
37         }
38     }
39 }
40 
41 void User::change_password(){
42     cout<<"Enter old password: ";
43     int count=0;
44     string b,b_2;
45     while(cin>>b){
46         if(b==password){
47             cout<<"Enter new password: ";
48             cin>>b_2;
49             password=b_2;
50             cout<<"new password is set successfully..."<<endl;
51             break;
52         }else{
53             count++;
54             if(count==3){
55                 cout<<"password input error. Please try after a while."<<endl;
56                 break;
57             }
58             cout<<"password input error. Please re-enter angain: ";
59         }
60     }
61 }
62 
63 void User::display() const{
64     cout<<"name: "<<name<<endl;
65     cout<<"pass: "<<string(password.length(),'*')<<endl;
66     cout<<"email: "<<email<<endl;
67 }

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 }

结果截图：

6.实验任务6

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

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)
 7     :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 void SavingsAccount::deposit(const Date &date, double  amount, const string& desc){
26     record(date,amount,desc);
27     }
28     void SavingsAccount::withdraw(const Date& date, double amount, const string& desc){
29         if (amount > getBalance())
30         error("not enough money");
31         else
32             record(date,-amount,desc);
33 
34     }
35         void SavingsAccount::settle(const Date& date) {
36     double interest = accumulate(date) * rate
37         / date.distance(Date(date.getYear() - 1, 1, 1));
38     if (interest != 0)
39         record(date, interest, "interest");
40     accumulation=0;
41 
42 }
43 void SavingsAccount::show()const {
44     cout << id << "\tBalance:" << balance;
45 }

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 }
19 public:
20     SavingsAccount(const Date& date, const std::string& id, double rate);
21     const std::string& getId()const { return id;}
22     double getBalance()const { return balance; }
23     double getRate()const { return rate; }
24     static double getTotal() { return total; }
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_ _

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 }

date.h

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

结果截图：

posted @ 2024-11-06 13:58 lbldmx 阅读(7) 评论(0) 编辑收藏举报

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lbldmx

实验3 类和对象_基础编程2

公告