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 class Button{
10 public:
11 Button(const string &text);
12 string get_label() const;
13 void click();
14 private:
15 string label;
16 };
17 Button::Button(const string &text):label{text}{
18 }
19 inline string Button::get_label() const {
20 return label;
21 }
22
23 void Button::click(){
24 cout << "Button'" << label << "'clicked\n";
25 }
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 class window{
11 public:
12 window(const string &win_title);
13 void display() const;
14 void close();
15 void add_button(const string &label);
16 private:
17 string title;
18 vector<Button> buttons;
19 };
20 window::window(const string &win_title):title{win_title}{
21 buttons.push_back(Button("close"));
22 }
23
24 inline void window::display() const {
25 string s(40,'*');
26
27 cout << s << endl;
28 cout << "window title:" << title << endl;
29 cout << "It has " << buttons.size() << "buttons: " << endl;
30 for(const auto &i:buttons)
31 cout << i.get_label() << "button" << endl;
32 cout << s << endl;
33 }
34
35 void window::close(){
36 cout << "close window '" << title << "'" << endl;
37 buttons.at(0).click();
38 }
39
40 void window::add_button(const string &label){
41 buttons.push_back(Button(label));
42 }
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
问题1：自定义了Button类、Window类，使用到了标准库中的string类、vector类、iostream类；Button类和Window类存在组合关系。
问题2：不适合。Button类中click是修改目标状态，不适合加const,同时涉及到输出操作，不适合设置成inline;
Window类中display较长，不适合设置成inline；close会调用click，不适合加const，同时close相对较长，不适合设置成inline;
问题3：创建s字符串，并初始化为包含40个*的字符串。
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 void output2(const vector<vector<int>> v){
12 for(auto &i:v){
13 for(auto &j:i)
14 cout << j << ", ";
15 cout << "\b\b \n";
16 }
17 }
18
19 void test1(){
20 vector<int> v1(5,42);
21 const vector<int> v2(v1);
22
23 v1.at(0) = -999;
24 cout << "v1: ";output1(v1);
25 cout << "v2: ";output1(v2);
26 cout << "v1.at(0) = " << v1.at(0) << endl;
27 cout << "v2.at(0) = " << v2.at(0) << endl;
28 }
29
30 void test2(){
31 vector<vector<int>> v1{{1,2,3},{4,5,6,7}};
32 const vector<vector<int>> v2(v1);
33 v1.at(0).push_back(-999);
34 cout << "v1:\n";output2(v1);
35 cout << "v2:\n";output2(v2);
36
37 vector<int> t1 = v1.at(0);
38 cout << t1.at(t1.size()-1) << endl;
39
40 const vector<int> t2 = v2.at(0);
41 cout << t2.at(t2.size()-1) << endl;
42 }
43 int main(){
44 cout << "测试1:\n";
45 test1();
46 cout << "\n测试2:\n";
47 test2();
48 }
View Code
问题1：将v1初始化为42,42,42,42,42；复制构造v2，让v2初始化为v1的值；将v1内0号元素42替换成-999；
问题2：将v1初始化为{1,2,3},{4,5,6,7}；复制构造v2，让v2初始化为v1的值，v2的值不可改变；让v1内{1，2,3}最末尾加上-999；
问题3：让t1等于{1,2,3，-999}，然后输出t1中3号元素-999；让t2等于{1,2,3}，然后输出2号元素3.
问题4：深复制 ；需要。
任务3：
vectorInt.hpp:
1 #pragma once
2 #include <iostream>
3 #include <cassert>
4
5 using std::cout;
6 using std::endl;
7
8 class vectorInt{
9 public:
10 vectorInt(int n);
11 vectorInt(int n, int value);
12 vectorInt(const vectorInt &vi);
13 ~vectorInt();
14 int& at(int index);
15 const int& at(int index) const;
16 vectorInt& assign(const vectorInt &v);
17 int get_size() const;
18 private:
19 int size;
20 int *ptr;
21 };
22
23 vectorInt::vectorInt(int n): size{n}, ptr{new int[size]} {
24 }
25
26 vectorInt::vectorInt(int n, int value): size{n}, ptr{new int[size]} {
27 for(auto i = 0; i < size; ++i)
28 ptr[i] = value;
29 }
30
31 vectorInt::vectorInt(const vectorInt &vi): size{vi.size}, ptr{new int[size]} {
32 for(auto i = 0; i < size; ++i)
33 ptr[i] = vi.ptr[i];
34 }
35
36 vectorInt::~vectorInt() {
37 delete [] ptr;
38 }
39
40 const int& vectorInt::at(int index) const {
41 assert(index >= 0 && index < size);
42
43 return ptr[index];
44 }
45
46 int& vectorInt::at(int index) {
47 assert(index >= 0 && index < size);
48
49 return ptr[index];
50 }
51
52 vectorInt& vectorInt::assign(const vectorInt &v) {
53 delete[] ptr;
54 size = v.size;
55 ptr = new int[size];
56 for(int i = 0; i < size; ++i)
57 ptr[i] = v.ptr[i];
58 return *this;
59 }
60
61 int vectorInt::get_size() const {
62 return size;
63 }
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 void test1() {
14 int n;
15 cout << "Enter n: ";
16 cin >> n;
17 vectorInt x1(n);
18 for(auto i = 0; i < n; ++i)
19 x1.at(i) = i*i;
20 cout << "x1: "; output(x1);
21 vectorInt x2(n, 42);
22 vectorInt x3(x2);
23 x2.at(0) = -999;
24 cout << "x2: "; output(x2);
25 cout << "x3: "; output(x3);
26 }
27
28 void test2() {
29 const vectorInt x(5, 42);
30 vectorInt y(10, 0);
31 cout << "y: "; output(y);
32 y.assign(x);
33 cout << "y: "; output(y);
34 cout << "x.at(0) = " << x.at(0) << endl;
35 cout << "y.at(0) = " << y.at(0) << endl;
36 }
37
38 int main() {
39 cout << "测试1: \n";
40 test1();
41 cout << "\n测试2: \n";
42 test2();
43 }
View Code
问题1：深复制；
问题2：能正确运行；在const方法中返回一个非const引用，可能导致编译错误；
问题3：可以改，但意义不大。返回*this可以确保获得对同一对象的引用；
问题4：标准库可以自动扩展和缩减容量，自定义需要手动管理内存，容易内存泄漏；标准库能够在多种情况下提供较好的性能，自定义性能取决于实现语句，可能会表现不佳。
任务4：
matrix.hpp：
1 #pragma once
2 #include <iostream>
3 #include <cassert>
4
5 using std::cout;
6 using std::endl;
7
8 class Matrix {
9 public:
10 Matrix(int n, int m);
11 Matrix(int n);
12 Matrix(const Matrix &x);
13 ~Matrix();
14
15 void set(const double *pvalue);
16 void clear();
17 const double& at(int i, int j) const;
18 double& at(int i, int j);
19 int get_lines() const;
20 int get_cols() const;
21 void display() const;
22
23 private:
24 int lines;
25 int cols;
26 double *ptr;
27 };
28
29 Matrix::Matrix(int n, int m) : lines(n), cols(m) {
30 ptr = new double[n * m]();
31 }
32
33 Matrix::Matrix(int n) : Matrix(n, n) {}
34
35 Matrix::Matrix(const Matrix &x) : lines(x.lines), cols(x.cols) {
36 ptr = new double[lines * cols];
37 for (int i = 0; i < lines * cols; ++i) {
38 ptr[i] = x.ptr[i];
39 }
40 }
41
42 Matrix::~Matrix() {
43 delete[] ptr;
44 }
45
46 void Matrix::set(const double *pvalue) {
47 for (int i = 0; i < lines; ++i) {
48 for (int j = 0; j < cols; ++j) {
49 ptr[i * cols + j] = pvalue[i * cols + j];
50 }
51 }
52 }
53
54 void Matrix::clear() {
55 for (int i = 0; i < lines * cols; ++i) {
56 ptr[i] = 0.0;
57 }
58 }
59
60 const double& Matrix::at(int i, int j) const {
61 assert(i >= 0 && i < lines && j >= 0 && j < cols);
62 return ptr[i * cols + j];
63 }
64
65 double& Matrix::at(int i, int j) {
66 assert(i >= 0 && i < lines && j >= 0 && j < cols);
67 return ptr[i * cols + j];
68 }
69
70 int Matrix::get_lines() const {
71 return lines;
72 }
73
74 int Matrix::get_cols() const {
75 return cols;
76 }
77
78 void Matrix::display() const {
79 for (int i = 0; i < lines; ++i) {
80 for (int j = 0; j < cols; ++j) {
81 cout << at(i, j) << " ";
82 }
83 cout << endl;
84 }
85 }
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 for(auto j = 0; j < m.get_cols(); ++j)
14 cout << m.at(index, j) << ", ";
15 cout << "\b\b \n";
16 }
17
18 void test1() {
19 double x[1000] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
20 int n, m;
21 cout << "Enter n and m: ";
22 cin >> n >> m;
23 Matrix m1(n, m);
24 m1.set(x);
25 Matrix m2(m, n);
26 m2.set(x);
27 Matrix m3(2);
28 m3.set(x);
29 cout << "矩阵对象m1: \n"; m1.display(); cout << endl;
30 cout << "矩阵对象m2: \n"; m2.display(); cout << endl;
31 cout << "矩阵对象m3: \n"; m3.display(); cout << endl;
32 }
33
34 void test2() {
35 Matrix m1(2, 3);
36 m1.clear();
37 const Matrix m2(m1);
38 m1.at(0, 0) = -999;
39 cout << "m1.at(0, 0) = " << m1.at(0, 0) << endl;
40 cout << "m2.at(0, 0) = " << m2.at(0, 0) << endl;
41 cout << "矩阵对象m1第0行: "; output(m1, 0);
42 cout << "矩阵对象m2第0行: "; output(m2, 0);
43 }
44
45 int main() {
46 cout << "测试1: \n";
47 test1();
48 cout << "测试2: \n";
49 test2();
50 }
View Code
任务5：
user.hpp:
1 #pragma once
2
3 #include<iostream>
4 #include<string>
5 #include<vector>
6
7 using namespace std;
8
9 class User {
10 public:
11 User(const string &name, const string &password = "123456", const string &email = "");
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(const string &name, const string &password = "123456", const string &email = "")
22 : name(name), password(password), email(email) {}
23
24 void set_email() {
25 cout << "Enter email address: ";
26 cin >> email;
27 cout << "email is set successfully..." << endl;
28 }
29
30 void change_password() {
31 string old_password;
32 cout << "Enter old password: ";
33 cin >> old_password;
34 int i = 1;
35 while (i < 3) {
36 if (old_password == password) {
37 string new_password;
38 cout << "Enter new password: ";
39 cin >> new_password;
40 password = new_password;
41 cout << "eew password is set successfully..." << endl;
42 return;
43 } else {
44 cout << "password input error. Please re-enter again: ";
45 cin >> old_password;
46 i++;
47 }
48 }
49 cout << "password input error. Please try after a while." << endl;
50 }
51
52 void display() const {
53 cout << "name: " << name << endl;
54 cout << "pass: " << string(password.length(), '*') << endl;
55 cout << "email: " << email << endl;
56 }
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", "[email protected]");
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
任务6：
date.h:
1 #ifndef __DATE_H__
2 #define __DATE_H__
3
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__
View Code
date.cpp:
1 #include "date.h"
2 #include <iostream>
3 #include <cstdlib>
4 using namespace std;
5
6 namespace {
7 const int DAYS_BEFORE_MONTH[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
8 }
9 Date::Date(int year, int month, int day) : year(year), month(month), day(day) {
10 if (day <= 0 || day > getMaxDay()) {
11 cout << "Invalid date.";
12 show();
13 cout << endl;
14 exit(1);
15 }
16 int years = year - 1;
17 totalDays = years * 365 + years / 4 - years / 100 + years / 400
18 + DAYS_BEFORE_MONTH[month-1] + day;
19 if (isLeapYear() && month > 2) totalDays++;
20 }
21 int Date::getMaxDay()const {
22 if (isLeapYear() && month == 2) {
23 return 29;
24 }
25 else {
26 return DAYS_BEFORE_MONTH[month] - DAYS_BEFORE_MONTH[month - 1];
27 }
28 }
29 void Date::show() const {
30 cout << getYear() << '-' << getMonth() << '-' << getDay();
31 }
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 void error(const std::string& msg) const;
15 double accumulate(const Date& date) const {
16 return accumulation + balance * date.distance(lastDate);
17 }
18 public:
19 SavingsAccount(const Date& date, const std::string& id, double rate);
20 const std::string& getId() const { return id; }
21 double getBalance() const { return balance; }
22 double getRate() const { return rate; }
23 static double getTotal() { return total; }
24 void deposit(const Date& date, double amount, const std::string& desc);
25 void withdraw(const Date& date, double amount, const std::string& desc);
26 void settle(const Date& date);
27 void show() const;
28 };
29 #endif // ACCOUNT_H
View Code
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 std::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 std::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 std::string& msg) const {
20 cout << "Error(#" << id << "): " << msg << endl;
21 }
22 void SavingsAccount::deposit(const Date& date, double amount, const std::string& desc) {
23 record(date, amount, desc);
24 }
25 void SavingsAccount::withdraw(const Date& date, double amount, const std::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 /date.distance(Date(date.getYear()-1,1,1));
33 if (interest != 0)
34 record(date, interest, "interest");
35 accumulation = 0;
36 }
37 void SavingsAccount::show() const {
38 cout << id << "\tBalance: " << balance;
39 }
View Code
6_25.cpp:
1 #include "account.h"
2 #include <iostream>
3 using namespace std;
4
5 int main() {
6 Date date(2008, 11, 1);
7 SavingsAccount accounts[] = {
8 SavingsAccount(date, "03755217", 0.015),
9 SavingsAccount(date, "02342342", 0.015)
10 };
11 const int n = sizeof(accounts) / sizeof(SavingsAccount); //账户总数
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 }
View Code
总结：
浅复制：浅复制创建一个新对象，但它并不会递归地复制对象内部的所有嵌套对象。相反，浅复制会复制对象的引用；
深复制：深复制则会创建一个新对象，并递归地复制所有嵌套对象。这样，新对象与原始对象之间完全独立，修改新对象中的任何内容都不会影响原始对象。
标签：std,const,cout,int,实验,include,string From： https://www.cnblogs.com/guguabiu/p/18525899