实验3

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", "Alice@hotmail.com");
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

 

posted @ 2024-11-08 17:13  _mao  阅读(8)  评论(0)  编辑  收藏  举报