实验任务1
button.hpp
1 #pragma once 2 3 #include <iostream> 4 #include <string> 5 6 using std::string; 7 using std::cout; 8 9 // 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
问题一:定义了window和button两个类,使用了标准库的string、vector、iostream类
问题二:不需要加const和inline 因为这些成员函数调用的时候不会对数据造成改变,而且其调用频率比较低,不需要变成内联函数
问题三:其功能是创建一个长度为30的字符串,每一个字符都是*
实验任务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: "; 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
问题一:第21行的代码是创建了一个名为v1的vector,包含五个元素,每个元素都是42
第22行的代码时创建了一个名为v2的vector,通过复制v1来初始化
第24行的代码是把v1的第0个元素改成-999,不影响v2
问题二:第32行代码创建了一个名为v1的二维vector
第33行代码创建了一个名为v2的二维vector,它通过复制v1来初始化,且值不能改变
第35行代码在v1索引为0的vector最后加一个元素-999
问题三:第39行代码创建了一个名为t1的int类型的vector,通过复制v1的第一个vector来初始化
第40行代码输出了t1最后一个元素的值
第42行代码创建了一个名为t2的int类型的vector,通过复制v2的第一个vector来初始化 ,且值不能被改变
第43行代码输出了t2最后一个元素的值
问题四:1、模板库内部封装的复制构造函数是浅复制;2、我觉得至少需要提供一个const成员作为接口,从而保证内部数据不易被改变
实验任务3
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
问题1:line14是深复制
问题2:将int&改成int后不能正常运行,at接口原来返回的是引用,允许直接修改元素值,改为int后返回的是值,意味着返回的是元素的拷贝,对原容器中值没有影响。line18前面的const删除返回值就变成了int&,允许修改元素值,与const成员函数相违背,存在安全隐患。
问题3:可以,但是不建议。返回一个新值可能会造成资源泄露,因为原对象中的资源在返回新对象后没有被正确释放。
实验任务4
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 Matrix::Matrix(int n,int m):lines{n},cols{m}{ 35 ptr=new double[n*m]; 36 } 37 Matrix::Matrix(int n){ 38 ptr=new double[n*n]; 39 } 40 Matrix::~Matrix(){ 41 delete []ptr; 42 } 43 void Matrix::clear(){ 44 for(int i=0;i<lines*cols;++i){ 45 ptr[i]=0; 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 Matrix::Matrix(const Matrix &x):lines{x.lines},cols{x.cols}{ 54 ptr=new double[lines*cols]; 55 for(int i=0;i<lines*cols;i++){ 56 ptr[i]=x.ptr[i]; 57 } 58 } 59 const double& Matrix::at(int i,int j)const { 60 return ptr[i*cols+j]; 61 } 62 double& Matrix::at(int i,int j){ 63 return ptr[i*cols+j]; 64 } 65 int Matrix::get_lines()const{ 66 return lines; 67 } 68 int Matrix::get_cols()const{ 69 return cols; 70 } 71 void Matrix::display()const{ 72 for(int i=0;i<lines*cols;i++){ 73 if((i+1)%cols!=0){ 74 cout<<ptr[i]<<" ,"; 75 }else{ 76 cout<<ptr[i]<<endl; 77 } 78 } 79 }View Code
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
实验任务5
user.hpp
1 #pragma once 2 #include<iostream> 3 #include<vector> 4 using namespace std; 5 using std::endl; 6 using std::cin; 7 using std::cout; 8 using std::string; 9 class User{ 10 public: 11 User(string Name,string Password="123456",string Email=""); 12 void set_email(); 13 void change_password(); 14 void display() const; 15 private: 16 string name,password,email; 17 }; 18 19 User::User(string Name,string Password,string Email):name(Name),password(Password),email(Email){}; 20 void set_email(){ 21 cout<<"Enter email address:"; 22 string email1; 23 int flag=1; 24 while(1){ 25 cin>>email1; 26 flag=1; 27 if(email1.find("@")!=-1){ 28 flag=0; 29 } 30 if (flag==0) { 31 break; 32 } 33 else{ 34 cout<<"illegal email.Please re-enter email:"; 35 } 36 }email=email1; 37 cout<<"email is set successfully..."<<endl; 38 } 39 40 void change_password(){ 41 cout<<"Enter old password:"; 42 int count,flag=1; 43 while(1){ 44 string password1; 45 if(password1!=password){ 46 cout<<"password input error.Please re-enter again:"; 47 count++; 48 }else{ 49 break; 50 }if(count==3){ 51 cout<<"password input error.Please try after a while."<<endl; 52 flag=0; 53 break; 54 } 55 }if (flag){ 56 cout<<"Enter new password:"; 57 cin>>password; 58 cout<<"new password is set successfully..."<<endl; 59 } 60 } 61 void display()const{ 62 int length=0; 63 length=password.size(); 64 string str(length,'*'); 65 cout<<"name: " <<name<<endl; 66 cout<<"pass: " <<password<<endl; 67 cout<<"email: "<<email<<endl; 68 cout<<endl; 69 }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 { 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 }; 35 #endifView Code
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 }View Code
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{return year;} 9 int getMonth()const{return month;} 10 int getDay() const{return day;} 11 int getMaxDay() const; 12 bool isLeapYear()const{ 13 return year%4==0 && year%100!=0 ||year%400==0; 14 } 15 void show()const; 16 int distance(const Date &date)const{ 17 return totalDays-date.totalDays; 18 } 19 20 }; 21 #endif / / _DATE_H__View Code
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 }View Code
6.25.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 }View Code
标签:std,const,cout,对象,int,实验,using,include From: https://www.cnblogs.com/wyhzmd/p/18526021