实验3 c++
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 }
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 }
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 }
运行结果：
问题1：自定义了两个类——Button和Window；使用了标准库的string类和vector类；其中vector类与Button类存在组合关系，Window类中包含一个类型为Button的vector类。
问题2：click()与add_button()适合设置成Inline，因为频繁使用且函数内容简短。
问题3：定义一个字符串s，其中包含40个‘*’。
任务2：
task2.cpp
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 }
运行结果：
问题1：1：创建一个长度为5，每个元素值为42的整型向量v1；2：将v1拷贝给v2；3：使v1的首个元素值赋为-999.
问题2：1.创建一个二维向量v1，第一行为｛1，2，3｝，第二行为｛4，5，6，7｝；2.将v1拷贝给v2；3.在v1的末尾添加一个新元素-999.
问题3：1.定义一个整型向量t1，其中包含v1的第一行元素；2.输出v1的第一行的最后一个元素；3.定义一个const（无法修改）的整型向量t2，包含v2的第一行元素；4.输出v2的第一行的最后一个元素。
任务3：
vectorInt.h
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 }
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 }
运行结果：
问题1：创建了新的指针并为其开辟空间，是深复制。
问题2：1.不能正常运行；
2.仍能正常运行。有潜在安全隐患，去掉const后返回值类型为int&，在后续操作中可能会改变引用类型的值。
问题3：可以。该函数作用为拷贝一个vectorInt类型的对象，加不加引用原来的值都会被修改。
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) { 35 lines=n; 36 cols=m; 37 ptr=new double[n*m]; 38 } 39 40 Matrix::Matrix(int n) { 41 lines=n; 42 cols=n; 43 ptr=new double[n*n]; 44 } 45 46 Matrix::Matrix(const Matrix &x) { 47 lines=x.lines; 48 cols=x.cols; 49 ptr=new double[lines*cols]; 50 for(int i=0;i<lines*cols;i++) { 51 ptr[i]=x.ptr[i]; 52 } 53 } 54 55 Matrix::~Matrix() { 56 delete[] ptr; 57 } 58 59 void Matrix::set(const double *pvalue) { 60 for(int i=0;i<lines*cols;i++){ 61 ptr[i]=pvalue[i]; 62 } 63 } 64 65 void Matrix::clear() { 66 for(int i=0;i<lines*cols;i++){ 67 ptr[i]=0; 68 } 69 } 70 71 const double& Matrix::at(int i,int j) const{ 72 assert(i>=0 && i<lines && j>=0 && j<cols); 73 return ptr[i*cols+j]; 74 } 75 76 double& Matrix::at(int i, int j) { 77 assert(i>=0 && i<lines && j>=0 && j<cols); 78 return ptr[i*cols+j]; 79 } 80 81 int Matrix::get_lines() const{ 82 return lines; 83 } 84 85 int Matrix::get_cols() const{ 86 return cols; 87 } 88 89 void Matrix::display() const{ 90 int i,j; 91 for(i=0;i<lines;i++){ 92 for(j=0;j<cols-1;j++){ 93 cout<<ptr[i*cols+j]<<", "; 94 } 95 cout<<ptr[i*cols+j]<<endl; 96 } 97 }
task4.cpp
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 }
运行结果：
任务5：
user.hpp
1 #pragma once 2 #include <iostream> 3 #include <string> 4 #include <iomanip> 5 6 using namespace std; 7 8 class User{ 9 public: 10 User(string n); 11 User(string n,string p,string e); 12 13 void set_email(); 14 void change_password(); 15 void display(); 16 private: 17 string name,password,email; 18 }; 19 20 User::User(string n){ 21 name=n; 22 password="123456"; 23 } 24 25 User::User(string n,string p,string e){ 26 name=n; 27 password=p; 28 email=e; 29 } 30 31 void User::set_email() { 32 cout<<"Enter email address:"; 33 cin>>email; 34 bool flag=false; 35 for(int i=0;i<sizeof(email);i++) { 36 if(email[i]=='@') 37 flag=true; 38 } 39 while(flag==false){ 40 cout<<"illegal email.Please re-enter email:"; 41 cin>>email; 42 for(int i=0;i<sizeof(email);i++) { 43 if(email[i]=='@') 44 flag=true; 45 } 46 } 47 cout<<"email is set successfully..."<<endl; 48 } 49 50 void User::change_password() { 51 int count=1; 52 string old_password; 53 cout<<"Enter old password:"; 54 cin>>old_password; 55 while(old_password!=password && count<=3){ 56 if(count<3){ 57 cout<<"password input error.Please re-enter again:"; 58 cin>>old_password; 59 count++; 60 } 61 else if(count==3){ 62 cout<<"password input error.Please try after a while."<<endl; 63 count++; 64 } 65 } 66 if(old_password==password){ 67 cout<<"Enter new password:"; 68 cin>>password; 69 cout<<"new password is set successfully..."<<endl; 70 } 71 } 72 73 void User::display() { 74 cout<<left<<setw(8)<<"name:"<<name<<endl; 75 cout<<left<<setw(8)<<"pass:"; 76 int l=sizeof(password); 77 for(int i=0;i<l;i++) 78 cout<<'*'; 79 cout<<endl; 80 cout<<left<<setw(8)<<"email:"<<email<<endl; 81 82 }
task5.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 }
运行结果：
任务6：
date.h
1 #pragma once 2 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 int distance(const Date& date)const { 20 return totalDays-date.totalDays; 21 } 22 };
date.cpp
1 #include"date.h" 2 #include<iostream> 3 #include<cstdlib> 4 5 using namespace std; 6 7 namespace { 8 const int DAYS_BEFIRE_MONTH[] = { 0,31,59,90,120,151,181,212,243,273,304 ,334,365 }; 9 } 10 Date::Date(int year, int month, int day) :year(year), month(month), day(day) { 11 if (day<= 0 || day>getMaxDay()) { 12 cout<<"Invalid date: "; 13 show(); 14 cout<<endl; 15 exit(1); 16 } 17 int years=year-1; 18 totalDays=years*365+years/4-years/100+years/400+DAYS_BEFIRE_MONTH[month-1]+day; 19 if (isLeapYear() && month>2) totalDays++; 20 } 21 int Date::getMaxDay() const { 22 if (isLeapYear() &&month==2) 23 return 29; 24 else return DAYS_BEFIRE_MONTH[month]-DAYS_BEFIRE_MONTH[month-1]; 25 } 26 void Date::show()const { 27 cout<<getYear()<<"-"<<getMonth()<<"-"<<getDay(); 28 }
account.h
1 #pragma once 2 #include"date.h" 3 #include<string> 4 5 using namespace std; 6 7 class SavingsAccount { 8 private: 9 string id; 10 double balance; 11 double rate; 12 Date lastDate; 13 double accumulation; 14 static double total; 15 void record(const Date& date,double amount,const string& desc); 16 void error(const string& msg) const; 17 double accumulate(const Date& date) const { 18 return accumulation+balance*date.distance(lastDate); 19 } 20 public: 21 SavingsAccount(const Date& date,const string& id,double rate); 22 const string& getId() const {return id;} 23 double getBalance() const {return balance;} 24 double getRate()const {return rate;} 25 static double getTotal() {return total;} 26 void deposit(const Date& date,double amount,const string& desc); 27 void withdraw(const Date& date,double amount,const string& desc); 28 void settle(const Date& date); 29 void show() const; 30 };
account.cpp
1 #include"account.h" 2 #include<cmath> 3 #include<iostream> 4 5 using namespace std; 6 7 double SavingsAccount::total = 0; 8 SavingsAccount::SavingsAccount(const Date& date,const string& id,double rate) : 9 id(id), balance(0), rate(rate), lastDate(date), accumulation(0) { 10 date.show(); 11 cout<<"\t#"<<id <<"created"<<endl; 12 } 13 void SavingsAccount::record(const Date& date,double amount,const string& desc) { 14 accumulation=accumulate(date); 15 lastDate=date; 16 amount=floor(amount*100+0.5)/100; 17 balance+=amount; 18 total+=amount; 19 date.show(); 20 cout<<"\t#"<<id<<"\t"<<amount<<"\t"<<balance<<"\t"<<desc<<endl; 21 } 22 void SavingsAccount::error(const string& msg) const { 23 cout<<"Error(#" << id << "):"<<msg<<endl; 24 } 25 void SavingsAccount::deposit(const Date& date,double amount,const string& desc) { 26 record(date,amount,desc); 27 } 28 void SavingsAccount::withdraw(const Date& date,double amount,const string& desc) { 29 if (amount>getBalance()) 30 error("not enough money"); 31 else 32 record(date,-amount,desc); 33 } 34 void SavingsAccount::settle(const Date& date) { 35 double interest=accumulate(date)*rate/date.distance(Date(date.getYear()-1,1,1)); 36 if (interest!=0) record(date,interest,"interest"); 37 accumulation=0; 38 } 39 void SavingsAccount::show() const { 40 cout<<id<<"\tBalance: "<<balance; 41 }
6_25.cpp
1 #include"account.h" 2 #include<iostream> 3 4 using namespace std; 5 6 int main(){ 7 Date date{2008,11,1}; 8 SavingsAccount accounts[] = { 9 SavingsAccount(date,"03755217",0.015), 10 SavingsAccount(date,"02342342",0.015) 11 }; 12 const int n=sizeof(accounts)/sizeof(SavingsAccount); 13 accounts[0].deposit(Date(2008,11,5),5000,"salary"); 14 accounts[1].deposit(Date(2008,11,25),10000,"sell stock 0323"); 15 accounts[0].deposit(Date(2008,12,5),5500,"salary"); 16 accounts[1].withdraw(Date(2008,12,20),4000,"buy a laptop"); 17 cout<<endl; 18 for(int i=0;i<n;i++) { 19 accounts[i].settle(Date(2009,1,1)); 20 accounts[i].show(); 21 cout<<endl; 22 } 23 cout<<"Total: "<<SavingsAccount::getTotal()<<endl; 24 return 0; 25 }
运行结果：
