task1
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
问题1：
自定义两个类按钮类和窗口类。使用标准库的vector和string。按钮类和窗口类之间存在组合关系。
问题2：
click和close适合加inline和const。
函数都小且被频繁调用，加inline有利于提高效率。
click和close不修改成员变量，添加const有利于提高安全性。
问题3：
创建一个长度为40的字符串，每个位置由'*'填充。
task2
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
问题1：
line1：创建名为v1的vector，有5个元素：42。
line2：创建名为v2的vector，用v1复制构造初始化。
line3：v1第一个元素设置为-999
问题2：
line1：创建一个vector名为v1里面存放两个int型vector。一个内容为1，2，3另一个4，5，6，7。
line2：创建存放int型vector的vector名为v2，用v1复制构造初始化。vector为const不可以修改。
line3：在v1第一个容器1，2，3后追加元素-999。
问题3：
line1：创建名为t1的int型vector，用v1第一个元素初始化。
line2：输出t1中最后一个元素。
line3：用v2第一个元素初始化名为t2的int型容器。const型不可修改。
line4：输出t2中最后一个元素。
问题4：
1.深复制2.不需要
task3
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
问题1：
深复制
问题2：
不能正确运行。x1.at(i)=i*i与x2.at(0)=-999报错。无法通过at方法修改元素。
安全隐患：可以通过返回引用值修改对象。比如const vectorInt x(5,42);
问题3：
不可以。原本修改对象变为了创建返回一个新对象。
task4
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 // xxx
36 Matrix::Matrix(int n,int m):lines(n),cols(m),ptr(new double[n*m]()){}
37
38 Matrix::Matrix(int n):lines(n),cols(n),ptr(new double[n*n]()){}
39
40 Matrix::Matrix(const Matrix &x):lines(x.lines),cols(x.cols),ptr(new double[lines*cols]()){
41 for(int i=0;i<lines*cols;i++)
42 ptr[i]=x.ptr[i];
43 }
44
45 Matrix::~Matrix(){
46 delete[] ptr;
47 }
48
49 void Matrix::set(const double *pvalue){
50 for(int i=0;i<lines*cols;i++)
51 ptr[i]=pvalue[i];
52 }
53
54 void Matrix::clear(){
55 for(int i=0;i<lines*cols;i++)
56 ptr[i]=0.0;
57 }
58
59 const double& Matrix::at(int i,int j) const
60 {
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 {
67 assert(i>=0&&i<lines&&j>=0&&j<cols);
68 return ptr[i*cols+j];
69 }
70
71 int Matrix::get_lines() const{
72 return lines;
73 }
74
75 int Matrix::get_cols() const{
76 return cols;
77 }
78
79 void Matrix::display() const{
80 for(int i=0;i<lines;i++){
81 for(int j=0;j<cols;j++){
82 cout<<at(i,j)<<" ";
83 }
84 cout<<endl;
85 }
86 }
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, 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 }
task4.cpp
task5
1 #pragma once
2
3 #include<iostream>
4 #include<string>
5 #include<vector>
6
7 using std::cin;
8 using std::cout;
9 using std::endl;
10 using std::vector;
11 using std::string;
12
13 class User{
14 public:
15 User (const string& name,const string& password="123456",const string& email="");
16 void set_email(bool isfirstcall=true);
17 void change_password();
18 void display() const;
19
20 private:
21 string name;
22 string password;
23 string email;
24 };
25
26 User::User(const string& name,const string& password,const string& email):name{name},password{password},email{email}{}
27
28 void User::set_email(bool isfirstcall){
29 if(isfirstcall){
30 cout<<"Enter email address:";
31 }
32 cin>>email;
33 bool is_valid;
34 vector<string> v{email};
35 for(auto &email:v){
36 auto pos=email.find("@");
37 if(pos==email.npos)
38 is_valid=false;
39 else
40 is_valid=true;
41 if(is_valid)
42 cout<<"email is set successfully..."<<endl;
43 else{
44 cout<<"illegal email.Please re-enter angain:";
45 set_email(false);
46 }
47 }
48 }
49
50 void User::change_password(){
51 string s;
52 int count=0;
53 cout<<"Enter old password:";
54 cin>>s;
55 while(true){
56 if(s!=password){
57 cout<<"password input error.";
58 count++;
59 }
60 else{
61 cout<<"Enter new password:";
62 cin>>password;
63 cout<<"new password is set successfully";
64 return;
65 }
66 if(count==3){
67 cout<<"Please try after a while.";
68 return;
69 }
70 else{
71 cout<<"Please re-enter angain:";
72 cin>>s;
73 }
74 }
75 }
76
77 void User::display()const{
78 cout<<"name: "<<name<<endl;
79 string s(password.size(),'*');
80 cout<<"pass: "<<s<<endl;
81 cout<<"email: "<<email<<endl;
82 }
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
task6
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 int distance(const Date& date) const {
19 return totalDays-date.totalDays;
20 }
21 };
date.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
17 +DAYS_BEFORE_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_BEFORE_MONTH[month]-DAYS_BEFORE_MONTH[month-1];
25 }
26 void Date::show()const{
27 cout<<getYear()<<"-"<<getMonth()<<"-"<<getDay();
28 }
date.cpp
1 #pragma once
2 #include"date.h"
3 #include<string>
4 using namespace std;
5 class SavingsAccount {
6 private:
7 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 string& desc);
14 void error(const 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 string& id, double rate);
20 const 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 string& desc);
25 void withdraw(const Date& date, double amount, const string& desc);
26 void settle(const Date& date);
27 void show() const;
28 };
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) :
7 id(id), balance(0), rate(rate), lastDate(date), accumulation(0) {
8 date.show();
9 cout << "\t#" << id << "created" << endl;
10 }
11 void SavingsAccount::record(const Date& date, double amount, const string& desc) {
12 accumulation = accumulate(date);
13 lastDate = date;
14 amount = floor(amount * 100 + 0.5) / 100;
15 balance += amount;
16 total += amount;
17 date.show();
18 cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl;
19 }
20 void SavingsAccount::error(const string& msg) const {
21 cout << "Error(#" << id << "):" << msg << endl;
22 }
23 void SavingsAccount::deposit(const Date& date, double amount, const string& desc) {
24 record(date, amount, desc);
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 void SavingsAccount::settle(const Date& date) {
33 double interest = accumulate(date) * rate / date.distance(Date(date.getYear() - 1, 1, 1));
34 if (interest != 0) record( date,interest,"interest" );
35 accumulation = 0;
36 }
37 void SavingsAccount::show()const {
38 cout << id << "\tBalance: " << balance;
39 }
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.cpp
标签：std,const,cout,int,实验,include,string From： https://www.cnblogs.com/mao08/p/18525609