实验任务1：
实验代码：
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
实验截图：
问题1：自定义了两个类，Button和Window；使用了标准库中两个类，string和vector；Button与string有组合关系，Window与string、Button、vector有组合关系。
问题2：Button类中的函数void click()适合设置成inline，该函数较小且简单，并且在实际应用中可能被多次调用。
问题3：生成一个string类对象s，其长度为40，且其中每个字符都为‘*’。
实验任务2：
实验代码：
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
实验截图：
问题1：第一行：定义一个int类型的vector数组v1，其长度为5，其中每个数据都为42。
第二行：定义一个int类型的vector数组v2，用v1的值来初始化。
第三行：将v1数组的第一个成员赋值为-999。
问题2：第一行：定义了一个int类型的名为v1的二维vector数组，第一个元素为vector数组{1，2，3}，第二个元素为vector数组{4，5，6，7}。
第二行：定义了一个int类型的名为v2的二维常量vector数组，用v1的值来初始化。
第三行：在二维vector数组v1第一个元素vector数组的末尾添加一个新元素-999。
问题3：第一行：定义一个int类型的vector数组t1，并用二维vector数组v1的第一个元素来初始化。
第二行：输出t1的最后一个元素的值。
第三行：定义了一个int类型的名为t2的常量vector数组，用v2的第一个元素来初始化。
第四行：输出t2的最后一个元素的值。
问题4：深复制；不需要。
实验任务3：
实验代码：
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 }
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
实验截图：
问题1：深复制。
问题2：可以正确运行。有安全隐患，const有助于保证数据不被意外修改。
问题3：可以改成。返回对象改成vectorInt后每次调用assign()函数会创建一个新的vectorInt对象，性能会降低但不影响实现。
实验任务4：
实验代码：
matrix.hpp:
1 #pragma once
2
3 #include <iostream>
4 #include <cassert>
5
6 using std::cout;
7 using std::endl;
8
9 // 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} {
36 ptr = new double[n*m];
37 }
38
39 Matrix::Matrix(int n): lines{n}, cols{n} {
40 ptr = new double[n*n];
41 }
42
43 Matrix::Matrix(const Matrix &x): lines{x.lines}, cols{x.cols} {
44 ptr = new double[lines*cols];
45 for(int i = 0; i < lines*cols; i++) ptr[i] = x.ptr[i];
46 }
47
48 void Matrix::set(const double *pvalue) {
49 for(int i = 0; i < lines*cols; i++)
50 ptr[i] = pvalue[i];
51 }
52
53 void Matrix::clear() {
54 for(int i = 0; i < lines*cols; i++)
55 ptr[i] = 0;
56 }
57
58 const double& Matrix::at(int i, int j) const {
59 assert(i >= 0 && i < lines && j >= 0 && j < cols);
60 return ptr[i*cols + j];
61 }
62
63 double& Matrix::at(int i, int j) {
64 assert(i >= 0 && i < lines && j >=0 && j < cols);
65 return ptr[i*cols + j];
66 }
67
68 int Matrix::get_lines() const {
69 return lines;
70 }
71
72 int Matrix::get_cols() const {
73 return cols;
74 }
75
76 void Matrix::display() const {
77 for(int i = 0; i < lines; i++) {
78 for(int j = 0; j < cols; j++)
79 cout << ptr[i*cols + j] << ", ";
80 cout << "\n";
81 }
82 }
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 }
View Code
实验截图：
实验任务5：
实验代码：
user.hpp:
1 #pragma once
2
3 #include <iostream>
4 #include <vector>
5 #include <string>
6
7 using namespace std;
8
9 class User {
10 public:
11 User(const string& name0, const string& password0 = "123456", const string& email0 = " ");
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::User(const string& name0, const string& password0, const string& email0) : name{name0}, password{password0}, email{email0} {}
22 void User::set_email() {
23 string input_email;
24 cout << "Enter email address：";
25 cin >> input_email;
26 while(true) {
27 if(input_email.find('@') != string::npos) {
28 email = input_email;
29 cout << "email is set successfully..." << endl;
30 break;
31 }
32 else {
33 cout << "illegal email. Please re-enter email：";
34 cin >> input_email;
35 }
36 }
37 }
38
39 void User::change_password() {
40 cout << "Enter old password：";
41 string input_password,newpassword;
42 int count = 0;
43 cin >> input_password;
44 while(count < 2) {
45 if(input_password == password) {
46 cout << "Enter new password：";
47 cin >> newpassword;
48 password = newpassword;
49 cout << "new password is set successfully..." << endl;
50 break;
51 }
52 else {
53 cout << "password input error. Please re-enter again: ";
54 cin >> input_password;
55 count++;
56 }
57 }
58 if(count == 2) {
59 cout << "password input error. Please try after a while." << endl;
60 }
61 }
62
63 void User::display() const {
64 cout << "用户名：" << name << endl;
65 cout << "密码：" << string(password.length(),'*') << endl;
66 cout << "邮箱：" << email << endl;
67 }
View Code
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
实验截图：
实验任务6：
实验代码：
date.h:
1 #pragma once
2 class Date {
3 private:
4 int year;
5 int month;
6 int day;
7 int totalDays;
8 public:
9 Date(int year, int month, int day);
10 int getYear() const {return year;}
11 int getMonth() const {return month;}
12 int getDay() const {return day;}
13 int getMaxDay() const;
14 bool isLeapYear() const {
15 return year%4==0 && year%100 != 0 || year%400==0;
16 }
17 void show() const;
18
19 int distance(const Date& date) const {
20 return totalDays-date.totalDays;
21 }
22 };
View Code
date.cpp:
1 #include "date.h"
2 #include<iostream>
3 #include<cstdlib>
4 using namespace std;
5 namespace {
6 const int DAYS_BEFIRE_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_BEFIRE_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_BEFIRE_MONTH[month] - DAYS_BEFIRE_MONTH[month - 1];
25 }
26 void Date::show()const {
27 cout << getYear() << "-" << getMonth() << "-" << getDay();
28 }
View Code
account.h:
1 #pragma once
2 #include "date.h"
3 #include <string>
4 class SavingsAccount {
5 private:
6 std::string id;
7 double balance;
8 double rate;
9 Date lastDate;
10 double accumulation;
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 {return id;}
23 double getBalance() const {return balance;}
24 double getRate() const {return rate;}
25 static double getTotal() {return total;}
26
27 void deposit(const Date &date, double amount, const std::string &desc);
28
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 };
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
13 void SavingsAccount::record (const Date &date, double amount, const string &desc) {
14 accumulation = accumulate(date);
15 lastDate = date;
16 amount = floor(amount*100 + 0.5)/100;
17 balance += amount;
18 total += amount;
19 date.show();
20 cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;
21 }
22
23 void SavingsAccount::error(const string &msg) const {
24 cout << "Error(#"<<id<<"): " << msg << endl;
25 }
26
27 void SavingsAccount::deposit(const Date &date, double amount, const string &desc) {
28 record(date, amount, desc);
29 }
30
31 void SavingsAccount::withdraw(const Date &date, double amount, const string &desc) {
32 if(amount > getBalance())
33 error("not enough money");
34 else
35 record(date, -amount, desc);
36 }
37
38 void SavingsAccount::settle(const Date &date) {
39 double interest = accumulate(date)*rate
40 / date.distance(Date(date.getYear()-1, 1, 1));
41 if(interest != 0)
42 record(date, interest, "interest");
43 accumulation = 0;
44 }
45
46 void SavingsAccount::show() const {
47 cout << id << "\tBalance: " << balance;
48 }
View Code
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 const int n = sizeof(accounts) / sizeof(SavingsAccount);
11 accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
12 accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
13
14 accounts[0].deposit(Date(2008, 12, 5), 5500, "salary");
15 accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop");
16
17 cout << endl;
18 for (int i = 0; i < n; i++) {
19 accounts[i].settle(Date(2009, 1, 1));
20 accounts[i].show();
21 cout << endl;
22 }
23 cout << "Total: " << SavingsAccount::getTotal() << endl;
24 return 0;
25 }
View Code
实验截图：
上面的程序增加了Date类，把对日期的表示均替换成了Date类型，输出效果比原来相比要直观的多。此外，本例广泛应用了字符串，这样在银行账号中可以出现字母，而且为每笔账目增加了说明文字，使得程序输出的信息更加丰富。
标签：const,string,int,void,实验,include,cout From： https://www.cnblogs.com/yyttsbb/p/18528479