任务1
源程序：
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 }
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 }
运行结果截图：
问题1：
定义了两个类，使用了标准库的string类，vector类，button与string类之间存在组合关系，window与button与vector之间存在组合关系。
问题2：
button中void click()和window中close()没有const，加const可以保护数据安全，而加inline则是在编译时就初始化数据，节省时间。
问题3：
初始化变量s,s的值为40个'*'
任务2
源码：
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 }
运行结果截图：
问题1：
21行表示定义初始化一个容器v1,v1容量大小为5，5个值都为int型整数，值都为5.
22行表示定义初始化一个容器v2,与v1完全一样
24行表示将容器v1中第一个元素赋值为-999
问题2：
32行表示定义一个容器v1,容器中有两个容器，值都为整形
33行表示将v1赋值给v2。
35行表示在v1容器中第一个元素后插入-999.
问题3：
39行表示将v1容器第一个元素初始化一个容器t1。
40行表示输出t1容器中的第四个元素输出
42表示将v2容器的第一个元素初始化一个容器t2
43表示输出t2容器的第三个元素输出
问题4：
1.深复制
2.需要
任务3
源程序
vectorInt.cpp
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 }
运行结果截图：
问题1：
浅复制
问题2：
不能，存在安全隐患，数据在返回时，可能被修改
问题3：
不能，因为返回的是地址
任务4
源程序
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),ptr{ new double[n*m] }{}
36
37 Matrix::Matrix(int n):lines(n),cols(n),ptr{ new double[n*n] }{}
38
39 Matrix::Matrix(const Matrix &x){
40 lines=x.lines;cols=x.cols;ptr=new double[x.lines*x.cols];
41 for(auto i=0;i<cols*lines;i++)
42 ptr[i]=x.ptr[i];
43 }
44
45 Matrix::~Matrix(){ delete [] ptr;}
46
47
48 void Matrix::set(const double *pvalue){
49 for(int i=0;i<cols*lines;i++)
50 ptr[i]=pvalue[i];
51 }
52 void Matrix::clear(){
53 for(auto i=0;i<cols*lines;i++)
54 ptr[i]=0;
55 }
56 const double& Matrix::at(int i, int j) const{
57 assert(i>=0&&i<lines&&j>=0&&j<cols);
58 return ptr[i*cols+j];
59 }
60 double& Matrix::at(int i, int j){
61 assert(i>=0&&i<lines&&j>=0&&j<cols);
62 return ptr[i*cols+j];
63 }
64 int Matrix::get_lines() const{
65 return lines;
66 }
67 int Matrix::get_cols() const{
68 return cols;
69 }
70 void Matrix::display()const {
71 for(auto i=0;i<lines;i++){
72 for(auto j=0;j<cols;j++){
73 cout << ptr[i*cols+j];
74 if(j!=cols- 1)cout << ","<<" ";
75 else cout << endl;
76 }
77
78
79 }
80 }
81 // xxx
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 }
运行结果截图：
任务5
源程序：
user.hpp
1 #pragma once
2 #include<string>
3 #include<iostream>
4 using namespace std;
5
6 class User{
7 public:
8 User(string n,string p="123456",string e="");
9 ~User();
10 //接口
11 void set_email();
12 void change_password();
13 void display();
14 private:
15 string name;
16 string password;
17 string email;
18 };
19 User::User(string n,string p,string e):name(n),password(p),email(e){}
20 User::~User(){}
21 void User::set_email(){
22 std::string test_email;
23
24 while (true) {
25 std::cout << "Enter email address: ";
26 std::cin >> test_email;
27
28 if (test_email.find('@') == std::string::npos) {
29 std::cout << "Illegal email. Please re-enter email: ";
30 } else {
31 email = test_email;
32 std::cout << "Email is set successfully..." << std::endl;
33 break;
34 }
35 }
36 }
37
38 void User::change_password(){
39 std::string old_password, new_password; // 定义 new_password
40 int attempts = 0;
41 const int max_attempts = 3;
42
43 while (attempts < max_attempts) {
44 std::cout << "Enter old password: ";
45 std::cin >> old_password;
46
47 if (old_password == password) {
48 std::cout << "Enter new password: ";
49 std::cin >> new_password;
50 password = new_password;
51 std::cout << "new password is set successfully..." << std::endl;
52 return;
53 } else {
54 attempts++;
55
56 if (attempts == max_attempts) {
57 std::cout << "password input error. Please try after a while." << std::endl;
58 } else {
59 std::cout << "password input error. Please re-enter again." << std::endl;
60 }
61
62 }
63 }
64 }
65 void User::display(){
66 cout << name << endl;
67 string s(password.size(),'*');
68 cout << s << endl;
69 cout << email << endl;
70 }
task.5.hpp
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", "[email protected]");
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 }
运行结果截图：
任务6：
源程序：
date.h
1 #ifndef __DATE_H__
2 #define __DATE_H__
3 class Date {
4 private:
5 int year,month,day,totalDays;
6 public:
7 Date(int year,int month,int day);
8 int getYear()const {
9 return year;
10 }
11 int getMonth()const {
12 return month;
13 }
14 int getDay() const {
15 return day;
16 }
17 int getMaxDay() const;
18 bool isLeapYear()const {
19 return year%4==0 && year%100!=0 ||year%400==0;
20 }
21 void show()const;
22 int distance(const Date &date)const {
23 return totalDays-date.totalDays;
24 }
25
26 };
27 #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 #ifndef __ACCOUNT_H__
2 #define __ACCOUNT_H__
3 #include "date.h"
4 #include <string>
5 class SavingsAccount {
6
7 private:
8 std::string id;
9 double balance,rate,accumulation;
10 Date lastDate;
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 {
23 return id;
24 }
25 double getBalance() const {
26 return balance;
27 }
28 double getRate() const {
29 return rate;
30 }
31 static double getTotal() {
32 return total;
33 }
34
35 void deposit(const Date& date, double amount, const std::string& desc);
36
37 void withdraw(const Date& date, double amount, const std::string& desc);
38
39 void settle(const Date& date);
40
41 void show() const;
42 };
43 #endif
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 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 void SavingsAccount::withdraw(const Date & date, double amount, const string& desc) {
26 if (amount > getBalance())
27 error("not enough money");
28 else
29 record(date, -amount, desc);
30 }
31 void SavingsAccount::settle(const Date& date) {
32 double interest = accumulate(date) * rate//计算年息
33 / date.distance(Date(date.getYear() - 1, 1, 1));
34 if (interest != 0)
35 record(date, interest, "interest");
36 accumulation = 0;
37 }
38 void SavingsAccount::show() const {
39 cout << id << "\tBalance:" << balance;
40 }
task6.cpp
1 #include "account.h"
2 #include <iostream>
3 using namespace std;
4 int main() {
5 //起始日期
6 Date date(2008, 11, 1);
7 //建立几个账户
8 SavingsAccount accounts[] = {
9 SavingsAccount(date,"03755217",0.015),
10 SavingsAccount(date, "02342342", 0.015)
11 };
12 const int n = sizeof(accounts) / sizeof(SavingsAccount); //账户总数
13
14 accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
15 accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
16
17 accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
18 accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
19
20 cout << endl;
21 for (int i = 0; i < n; i++) {
22 accounts[i].settle(Date(2009, 1, 1));
23 accounts[i].show();
24 cout << endl;
25 }
26 cout << "Total: " << SavingsAccount::getTotal() << endl;
27 return 0;
28 }
运行结果截图：
标签：std,const,string,对象,编程,int,实验,include,cout From： https://www.cnblogs.com/ltrbky/p/18538669