实验任务1
实验代码：
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 }
button.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 }
window.hpp
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 }
task1.cpp
运行结果截图：
问题：
问题1：
自定义了两个类：button和window;
使用标准库的类有：string,iostream,vector;
存在组合关系的类有：button,window;window中包含vector<Button> buttons.
问题2：
button 中click可以加const,因为它没改变类的成员。
Window中的close 也可以加const.
问题3：
输出边界和提示语。
实验任务2：
实验代码：
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 }
task2.cpp
运行结果截图：
问题：
问题1：
创建一个存放int 类型的vector对象V1,大小为5初始值为42
复制构造一个vector对象 v2，大小和成员都与v1相同。
将v1中的第一个元素改为-999.
问题2：
创建一个二维的vector 对象v1并初始化；
复制构造一个二维的vector 对象v2,它相当于vector 的一个副本；
在v1的第一个子vector末尾追加一个元素-999；
问题3：
将v1的第一个子vector赋值给t1;
输出t1最后一个元素；
将v2的第一个子vector赋值给t2;
输出t2最后一个元素；
问题4：
1.深复制；
2.需要提供。
实验任务3：
实验代码：
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 }
vectorInt.hpp
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 }
task3.cpp
运行结果截图：
问题：
问题1：
深复制；
问题2：
不能运行。
报错截图如下：
因为返回值不是引用类型的话，就无法完成修改成员值的操作，所以会报错。
有潜在安全隐患。可能会被错误调用。
问题3：
不可以改为vectorInt,这样的话，就不能利用诸如y.assign(x).at(0)=0这样的式子进一步修改y中的值；
实验任务4：
实验代码：
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) : lines{ n }, cols{ m }, ptr{ new double[lines * cols] } {}
35 Matrix::Matrix(int n) : lines{ n }, cols{ n }, ptr{ new double[lines * cols] } {}
36 Matrix::Matrix(const Matrix& x) : lines{ x.lines }, cols{ x.cols }, ptr{ new double[lines * cols] } {
37 for (int i = 0; i < lines * cols; ++i) {
38 ptr[i] = x.ptr[i];
39 }
40 }
41 Matrix::~Matrix() {
42 delete []ptr;
43 }
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 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 if(i >= 0 && i < lines && j >= 0 && j < cols)
60 return ptr[i * cols + j];
61 }
62 double& Matrix::at(int i, int j) {
63 if(i >= 0 && i < lines && j >= 0 && j < cols)
64 return ptr[i * cols + j];
65 }
66 int Matrix::get_lines() const { return lines; }
67 int Matrix::get_cols() const { return cols; }
68 void Matrix::display() const {
69 for (int i = 0; i < lines; ++i) {
70 for (int i1 = 0; i1 < cols; ++i1) {
71 cout << ptr[i * cols + i1] << ", ";
72 }
73 cout << "\b\b \n";
74 }
75 }
matrix.hpp
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] = {1,3,5,2,4,6,7,8,9};
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 }
task4.cpp
运行结果截图：
实验任务5：
实验代码：
1 #pragma once
2 #include <iostream>
3 #include <string>
4 #include <vector>
5
6 using std::string;
7 using std::cout;
8 using std::endl;
9 using std::vector;
10
11 class User {
12 public:
13 User(const string& name, const string& password = "123456", const string& email = "");
14 void set_email();
15 void change_password();
16 void display();
17 private:
18 string name;
19 string password;
20 string email;
21 };
22
23 User::User(const string& name, const string& password, const string& email) : name{ name }, password{ password }, email{ email } {}
24
25 void User::set_email() {
26 string input;
27 bool c = false;
28 cout << "Enter email address: ";
29 do {
30
31 std::cin >> input;
32 size_t pos = input.find('@');
33 if (pos != string::npos) {
34 c = true;
35 }
36 else {
37 cout << "illegal email. Please re-enter email: ";
38 }
39 } while (!c);
40 email = input;
41 cout << "email is set successfully..." << endl;
42 }
43
44 void User::change_password() {
45 string old_password;
46 string new_password;
47 int cnt = 0;
48 bool correct = false;
49 cout << "Enter old password: ";
50 do {
51
52 std::cin >> old_password;
53 if (old_password == password) {
54 correct = true;
55 }
56 else {
57 cnt++;
58 if (cnt == 3) {
59 cout << "password input error. Please try after a while." << endl;
60 return;
61 }
62 cout << "password input error. Please re-enter again: ";
63 }
64 } while (!correct);
65 cout << "Enter new password: ";
66 std::cin >> new_password;
67 password = new_password;
68 cout << "new password is set successfully..." << endl;
69 }
70
71 void User::display() {
72 cout << "name: " << name << endl;
73 string showpassword(password.length(), '*');
74 cout << "pass: " << showpassword << endl;
75 cout << "email: " << email << endl;
76 }
user.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_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 }
task5.cpp
运行结果截图：
实验任务6：
实验代码：
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 //__DATE_H__
data.h
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
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
27 void Date::show() const {
28 cout<<getYear()<<"-"<<getMonth()<<"-"<<getDay();
29 }
data.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
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
27 void Date::show() const {
28 cout<<getYear()<<"-"<<getMonth()<<"-"<<getDay();
29 }
account.h
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 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 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
26 void SavingsAccount::withdraw(const Date &date,double amount,const string &desc) {
27 if(amount>getBalance())
28 error("not enough money");
29 else
30 record(date,-amount,desc);
31 }
32
33 void SavingsAccount::settle(const Date &date) {
34 double interest=accumulate(date) * rate/date.distance(Date(date.getYear()-1,1,1));
35 if(interest!=0)
36 record(date,interest,"interest");
37 accumulation=0;
38 }
39 void SavingsAccount::show() const{
40 cout<<id<<"\tBalance:"<<balance;
41 }
account.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 accounts[0].deposit(Date(2008,12,5),5500,"salary");
14 accounts[1].withdraw(Date(2008,12,20),4000,"buy a laptop");
15 cout<<endl;
16 for(int i=0;i<n;i++){
17 accounts[i].settle(Date(2009,1,1));
18 accounts[i].show();
19 cout<<endl;
20 }
21 cout<<"Total: "<<SavingsAccount::getTotal()<<endl;
22 return 0;
23 }
6_25
运行结果截图：
优化：
将一些输出函数前加incline,可以提高代码运行效率。
标签：std,const,cout,对象,编程,int,实验,using,include From： https://www.cnblogs.com/faker007/p/18525829