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
15 private:
16 string label;
17 };
18
19 Button::Button(const string &text):label{text}{
20 }
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 #include "button.hpp"
2
3 #include<iostream>
4 #include<vector>
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
17 private:
18 string title;
19 vector<Button> buttons;
20 };
21
22 window::window(const string &win_title):title{win_title}{
23 buttons.push_back(Button("close"));
24 }
25
26 inline void window::display() const{
27 string s(40,'*');
28
29 cout << s <<endl;
30 cout << "window title: " << title << endl;
31 cout << "It has " << buttons.size() << " buttons: " << endl;
32 for(const auto &i:buttons)
33 cout << i.get_label() << " button" <<endl;
34 cout << s <<endl;
35 }
36
37 void window::close(){
38 cout << "close window '"<< title << "'" <<endl;
39 buttons.at(0).click();
40 }
41
42 void window::add_button(const string &label){
43 buttons.push_back(Button(label));
44 }
task1.cpp:
1 #include "window.hpp"
2
3 #include<iostream>
4
5 using std::cout;
6 using std::cin;
7
8 void test(){
9 window w1("new window");
10 w1.add_button("maximize");
11 w1.display();
12 w1.close();
13 }
14
15 int main(){
16 cout << "用组合类模拟简单GUI：\n";
17 test();
18 }
结果：
问题1：这个模拟简单GUI的示例代码中，自定义了几个类？使用到了标准库的哪几个类？，哪些类和类之间存在组合关系？ 答：button类和window类；用到了iostream类、string类、vector类； 问题2：在自定义类Button和Window中，有些成员函数定义时加了const, 有些设置成了inline。如果你是类的设计者，目前那些没有加const或没有设置成inline的，适合添加const，适合设置成inline吗？你的思考依据是？ 答：不适合。const不可更改数据元素，而inline可以提高执行效率。 问题3：类Window的定义中，有这样一行代码，其功能是？ 答：连续输出40个“*”号
任务2：
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: ";
26 output1(v1);
27 cout << "v2: ";
28 output1(v2);
29 cout << "v1.at(0) = " << v1.at(0) << endl;
30 cout << "v2.at(0) = " << v2.at(0) << endl;
31 }
32 void test2() {
33 vector<vector<int>> v1 {{1, 2, 3}, {4, 5, 6, 7}};
34 const vector<vector<int>> v2(v1);
35 v1.at(0).push_back(-999);
36 cout << "v1: \n";
37 output2(v1);
38 cout << "v2: \n";
39 output2(v2);
40 vector<int> t1 = v1.at(0);
41 cout << t1.at(t1.size()-1) << endl;
42 const vector<int> t2 = v2.at(0);
43 cout << t2.at(t2.size()-1) << endl;
44 }
45 int main() {
46 cout << "测试1:\n";
47 test1();
48 cout << "\n测试2:\n";
49 test2();
50 }
结果：
问题1：
vector<int> v1(5, 42); 创建一个含5个元素均为42的vector对象v1；
const vector<int> v2(v1);创建一个vector对象v2，初始值为v1；
v1.at(0) = -999; v1中索引为0的元素赋值为-999；
问题2：
vector<vector<int>> v1{{1, 2, 3}, {4, 5, 6, 7}}; 创建一个vector类对象，包含{1, 2, 3}和{4, 5, 6, 7}；
const vector<vector<int>> v2(v1);创建一个vector类对象v2，初始值为v1；
v1.at(0).push_back(-999); 在v1中索引为0的子vecto后面添加一个元素，它的值是-999
问题3：
vector<int> t1 = v1.at(0); 创建一个vector类对象t1，赋值为v1索引为0的子vector；
cout << t1.at(t1.size()-1) << endl; 输出t1的最后一个元素；
const vector<int> t2 = v2.at(0); 创建一个vector类对象t2，赋值为v2的索引为0的子vector；
cout << t2.at(t2.size()-1) << endl; 输出t2的最后一个元素
问题4：
（1）是深复制，因为v1和v2改变数据互不影响
（2）需要。
任务3：
vectorInt.hpp
#pragma once
#include <iostream>
#include <cassert>
using std::cout;
using std::endl;
// 动态int数组对象类
class vectorInt {
public:
vectorInt(int n);
vectorInt(int n, int value);
vectorInt(const vectorInt &vi);
~vectorInt();
int& at(int index);
const int& at(int index) const;
vectorInt& assign(const vectorInt &v);
int get_size() const;
private:
int size;
int *ptr; // ptr指向包含size个int的数组
};
vectorInt::vectorInt(int n): size {n}, ptr {new int[size]} {
}
vectorInt::vectorInt(int n, int value): size {n}, ptr {new int[size]} {
for(auto i = 0; i < size; ++i)
ptr[i] = value;
}
vectorInt::vectorInt(const vectorInt &vi): size {vi.size}, ptr {new int[size]} {
for(auto i = 0; i < size; ++i)
ptr[i] = vi.ptr[i];
}
vectorInt::~vectorInt() {
delete [] ptr;
}
const int& vectorInt::at(int index) const {
assert(index >= 0 && index < size);
return ptr[index];
}
int& vectorInt::at(int index) {
assert(index >= 0 && index < size);
return ptr[index];
}
vectorInt& vectorInt::assign(const vectorInt &v) {
delete[] ptr; // 释放对象中ptr原来指向的资源
size = v.size;
ptr = new int[size];
for(int i = 0; i < size; ++i)
ptr[i] = v.ptr[i];
return *this;
}
int vectorInt::get_size() const {
return size;
}
task3.cpp
1 #include "vectorInt.hpp"
2 #include <iostream>
3 using std::cin;
4 using std::cout;
5 void output(const vectorInt &vi) {
6 for(auto i = 0; i < vi.get_size(); ++i)
7 cout << vi.at(i) << ", ";
8 cout << "\b\b \n";
9 }
10 void test1() {
11 int n;
12 cout << "Enter n: ";
13 cin >> n;
14 vectorInt x1(n);
15 for(auto i = 0; i < n; ++i)
16 x1.at(i) = i*i;
17 cout << "x1: ";
18 output(x1);
19 vectorInt x2(n, 42);
20 vectorInt x3(x2);
21 x2.at(0) = -999;
22 cout << "x2: ";
23 output(x2);
24 cout << "x3: ";
25 output(x3);
26 }
27 void test2() {
28 const vectorInt x(5, 42);
29 vectorInt y(10, 0);
30 cout << "y: ";
31 output(y);
32 y.assign(x);
33 cout << "y: ";
34 output(y);
35 cout << "x.at(0) = " << x.at(0) << endl;
36 cout << "y.at(0) = " << y.at(0) << endl;
37 }
38 int main() {
39 cout << "测试1: \n";
40 test1();
41 cout << "\n测试2: \n";
42 test2();
43 }
结果：
问题1：深复制；
问题2：不能；存在安全隐患，此时返回值可被修改
问题3：可以，因为此时是深复制
任务4：
matrix.hpp
1 #pragma once
2 #include <iostream>
3 #include <cassert>
4 using std::cout;
5 using std::endl;
6 // 类Matrix的声明
7 class Matrix {
8 public:
9 Matrix(int n, int m); // 构造函数，构造一个n*m的矩阵, 初始值为value
10 Matrix(int n); // 构造函数，构造一个n*n的矩阵, 初始值为value
11 Matrix(const Matrix &x); // 复制构造函数， 使用已有的矩阵X构造
12 ~Matrix();
13 void set(const double *pvalue); // 用pvalue指向的连续内存块数据按行为矩阵赋值
14 void clear(); // 把矩阵对象的值置0
15 const double& at(int i, int j) const; // 返回矩阵对象索引(i,j)的元素const引用
16 double& at(int i, int j); // 返回矩阵对象索引(i,j)的元素引用
17 int get_lines() const; // 返回矩阵对象行数
18 int get_cols() const; // 返回矩阵对象列数
19 void display() const;
20 private:
21 int lines; // 矩阵对象内元素行数
22 int cols; // 矩阵对象内元素列数
23 double *ptr;
24 };
25 // 类Matrix的实现：待补足
26 Matrix::Matrix(int n,int m):lines {n},cols {m} {
27 ptr = new double[n*m];
28 }
29 Matrix::Matrix(int n) :lines { n }, cols { n } {
30 ptr = new double[n * n];
31 }
32 Matrix::Matrix(const Matrix& x) :lines { x.lines }, cols {x.cols} {
33 ptr = new double[lines * cols];
34 for (int i = 0; i < lines * cols; i++) ptr[i] = x.ptr[i];
35 }
36 Matrix::~Matrix() {
37 delete[] ptr;
38 }
39 void Matrix::set(const double* pvalue) {
40 for (int i = 0; i < lines * cols; i++)
41 ptr[i] = pvalue[i];
42 }
43 void Matrix::clear() {
44 for (int i = 0; i < lines * cols; i++)
45 ptr[i] = 0;
46 }
47 const double& Matrix::at(int i, int j) const {
48 assert(i >= 0 && i < lines && j >= 0 && j < cols);
49 return ptr[i * cols + j];
50 }
51 double& Matrix::at(int i, int j) {
52 assert(i >= 0 && i < lines && j >= 0 && j < cols);
53 return ptr[i * cols + j];
54 }
55 int Matrix::get_lines()const {
56 return lines;
57 }
58 int Matrix::get_cols()const {
59 return cols;
60 }
61 void Matrix::display() const {
62 for (int i = 0; i < lines; i++) {
63 for (int j = 0; j < cols; j++)
64 cout << ptr[i * cols + j] << ", ";
65 cout << "\b\b \n";
66 }
67 }
68 // xxx
task4.cpp
1 #include "matrix.hpp"
2 #include <iostream>
3 #include <cassert>
4 using std::cin;
5 using std::cout;
6 using std::endl;
7 const int N = 1000;
8 // 输出矩阵对象索引为index所在行的所有元素
9 void output(const Matrix &m, int index) {
10 assert(index >= 0 && index < m.get_lines());
11 for(auto j = 0; j < m.get_cols(); ++j)
12 cout << m.at(index, j) << ", ";
13 cout << "\b\b \n";
14 }
15 void test1() {
16 double x[1000] = {1, 2, 3, 4, 5, 6, 7, 8, 9};
17 int n, m;
18 cout << "Enter n and m: ";
19 cin >> n >> m;
20 Matrix m1(n, m); // 创建矩阵对象m1, 大小n×m
21 m1.set(x); // 用一维数组x的值按行为矩阵m1赋值
22 Matrix m2(m, n); // 创建矩阵对象m1, 大小m×n
23 m2.set(x); // 用一维数组x的值按行为矩阵m1赋值
24 Matrix m3(2); // 创建一个2×2矩阵对象
25 m3.set(x); // 用一维数组x的值按行为矩阵m4赋值
26 cout << "矩阵对象m1: \n";
27 m1.display();
28 cout << endl;
29 cout << "矩阵对象m2: \n";
30 m2.display();
31 cout << endl;
32 cout << "矩阵对象m3: \n";
33 m3.display();
34 cout << endl;
35 }
36 void test2() {
37 Matrix m1(2, 3);
38 m1.clear();
39 const Matrix m2(m1);
40 m1.at(0, 0) = -999;
41 cout << "m1.at(0, 0) = " << m1.at(0, 0) << endl;
42 cout << "m2.at(0, 0) = " << m2.at(0, 0) << endl;
43 cout << "矩阵对象m1第0行: ";
44 output(m1, 0);
45 cout << "矩阵对象m2第0行: ";
46 output(m2, 0);
47 }
48 int main() {
49 cout << "测试1: \n";
50 test1();
51 cout << "测试2: \n";
52 test2();
53 }
结果：
任务5：
User.hpp
1 #pragma once
2
3 #include<iostream>
4 #include<cassert>
5 #include<string>
6 #include<vector>
7
8 using namespace std;
9
10 class User {
11 public:
12 User(string username, string password = "123456", string userEmail = "");
13 ~User();
14
15 void set_email();
16 void change_password();
17 void display();
18
19
20
21
22 private:
23 string name;
24 string email;
25 string password;
26
27 };
28
29 User::User(string username, string password, string userEmail):name {username}, password {password}, email {userEmail} {
30 }
31
32 User::~User() {
33 }
34 void User::set_email() {
35 cout << "Enter email address: ";
36 while(1) {
37 string useremail;
38 cin >> useremail;
39 size_t pos = email.find('@');
40 if (pos != string::npos) {
41 email = useremail;
42 cout << "email is set successfully..." << endl;
43 break;
44 } else {
45 cout << "illegal email.Please re-enter email: ";
46 }
47 }
48 }
49
50
51
52 void User::change_password() {
53 string t;
54 cout << "Enter old password:" << endl;
55 int c = 0;
56 while(c < 3) {
57 cin >> t;
58 if(t.compare(password) == 0) {
59 break;
60 } else {
61 cout << "password input error. Please re-enter angain:" << endl;
62 cin.clear();
63 }
64 ++c;
65 }
66
67 if(c == 3) {
68 cout << "password input error. Please try after a while.";
69 } else {
70 cout << "Enter new password:" << endl;
71 cin >> password;
72 cout << "new password is set successfully...";
73 }
74 }
75
76
77 void User::display() {
78 cout << "name: " << name << endl;
79 cout << "pass: ";
80 for(int i = 0; i < password.size(); i++) {
81 cout << "*";
82 }
83 cout << endl;
84 cout << "eamil: " << email << endl;
85 }
task5.cpp
1 #include "user.hpp"
2 #include <iostream>
3 #include <vector>
4 #include <string>
5 using std::cin;
6 using std::cout;
7 using std::endl;
8 using std::vector;
9 using std::string;
10 void test() {
11 vector<User> user_lst;
12
13 User u1("Alice", "2024113", "[email protected]");
14 user_lst.push_back(u1);
15 cout << endl;
16
17 User u2("Bob");
18 u2.set_email();
19 u2.change_password();
20 user_lst.push_back(u2);
21 cout << endl;
22
23 User u3("Hellen");
24 u3.set_email();
25 u3.change_password();
26 user_lst.push_back(u3);
27 cout << endl;
28
29 cout << "There are " << user_lst.size() << " users. they are: " << endl;
30 for(auto &i: user_lst) {
31 i.display();
32 cout << endl;
33 }
34 }
35 int main() {
36 test();
37 }
结果：
任务6：
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 }
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 }
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 }
结果：
标签：std,const,cout,int,实验,include,string From： https://www.cnblogs.com/Bling888/p/18536758