任务一:
button.hpp:
#pragma once #include "button.hpp" #include <vector> #include <iostream> using std::vector; using std::cout; using std::endl; // 窗口类 class Window { public: Window(const string& win_title); void display() const; void close(); void add_button(const string& label); private: string title; vector<Button> buttons; }; Window::Window(const string& win_title) : title{ win_title } { buttons.push_back(Button("close")); } inline void Window::display() const { string s(40, '*'); cout << s << endl; cout << "window title: " << title << endl; cout << "It has " << buttons.size() << " buttons: " << endl; for (const auto& i : buttons) cout << i.get_label() << " button" << endl; cout << s << endl; } void Window::close() { cout << "close window '" << title << "'" << endl; buttons.at(0).click(); } void Window::add_button(const string& label) { buttons.push_back(Button(label)); }
window.hpp:
#pragma once #include "button.hpp" #include <vector> #include <iostream> using std::vector; using std::cout; using std::endl; // 窗口类 class Window { public: Window(const string& win_title); void display() const; void close(); void add_button(const string& label); private: string title; vector<Button> buttons; }; Window::Window(const string& win_title) : title{ win_title } { buttons.push_back(Button("close")); } inline void Window::display() const { string s(40, '*'); cout << s << endl; cout << "window title: " << title << endl; cout << "It has " << buttons.size() << " buttons: " << endl; for (const auto& i : buttons) cout << i.get_label() << " button" << endl; cout << s << endl; } void Window::close() { cout << "close window '" << title << "'" << endl; buttons.at(0).click(); } void Window::add_button(const string& label) { buttons.push_back(Button(label)); }
task1.cpp:
#include "window.hpp" #include <iostream> using std::cout; using std::cin; void test() { Window w1("new window"); w1.add_button("maximize"); w1.display(); w1.close(); } int main() { cout << "用组合类模拟简单GUI:\n"; test(); }
实验结果截图:
问题一:自定义了两个类使用了标准库的iostream,string,vector类,button类和iostream,string组合,window类和button,iostream,vector类组合
问题二:如果成员函数只是访问数据而不改变数据,就可以加上const来增加代码的安全性。如果函数简单并且调用频繁,则可以加上inline来提高性能
问题三:代码的功能是生成一条分割线,可用于装饰和视觉辅助。
任务二:
task2.cpp:
#include <iostream> #include <vector> using namespace std; void output1(const vector<int>& v) { for (auto& i : v) cout << i << ", "; cout << "\b\b \n"; } void output2(const vector<vector<int>> v) { for (auto& i : v) { for (auto& j : i) cout << j << ", "; cout << "\b\b \n"; } } void test1() { vector<int> v1(5, 42); const vector<int> v2(v1); v1.at(0) = -999; cout << "v1: ";output1(v1); cout << "v2: ";output1(v2); cout << "v1.at(0) = " << v1.at(0) << endl; cout << "v2.at(0) = " << v2.at(0) << endl; } void test2() { vector<vector<int>> v1{ {1, 2, 3}, {4, 5, 6, 7} }; const vector<vector<int>> v2(v1); v1.at(0).push_back(-999); cout << "v1: \n";output2(v1); cout << "v2: \n";output2(v2); vector<int> t1 = v1.at(0); cout << t1.at(t1.size() - 1) << endl; const vector<int> t2 = v2.at(0); cout << t2.at(t2.size() - 1) << endl; } int main() { cout << "测试1:\n"; test1(); cout << "\n测试2:\n"; test2(); }
实验结果截图:
问题一:创建一个整数向量v1,大小为5,所有元素初始化为42,创建向量v2,复制v1内容,并把v1的第一个元素改为-999。
问题二:创建一个二维向量v1,第一行为1,2,3、第二行为4、5、6、7,后创建一个v1的副本v2,最后在v1第一行的结尾插入-999
问题三:创建一个一维向量t1,拷贝v1第一行的内容,并输出t1的最后一个元素,同理t2。
问题四:vector内部封装的复制构造函数是深复制,为每个元素提供独立的副本。需要提供一个const成员函数作为接口,供const vector使用。
任务三:
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:
#include "vectorInt.hpp" #include <iostream> using std::cin; using std::cout; void output(const vectorInt& vi) { for (auto i = 0; i < vi.get_size(); ++i) cout << vi.at(i) << ", "; cout << "\b\b \n"; } void test1() { int n; cout << "Enter n: "; cin >> n; vectorInt x1(n); for (auto i = 0; i < n; ++i) x1.at(i) = i * i; cout << "x1: "; output(x1); vectorInt x2(n, 42); vectorInt x3(x2); x2.at(0) = -999; cout << "x2: "; output(x2); cout << "x3: "; output(x3); } void test2() { const vectorInt x(5, 42); vectorInt y(10, 0); cout << "y: "; output(y); y.assign(x); cout << "y: "; output(y); cout << "x.at(0) = " << x.at(0) << endl; cout << "y.at(0) = " << y.at(0) << endl; } int main() { cout << "测试1: \n"; test1(); cout << "\n测试2: \n"; test2(); }
实验结果截图:
问题一:是深复制,为新的代码对象分配了新的内存空间。
问题二:如果返回值改为int无法正确运行测试代码,因为无法通过at修改元素了,有潜在安全隐患,外部代码可能会修改内部数据。
问题三:不可以,如果返回值类型是 vectorint 而不是引用,则每次调用时,都会创建一个vectorint对象的副本。这意味着在函数返回之前,会发生一个完整的对象复制,对性能有显著影响。
任务四:
matrix.hpp:
#include <iostream> #include <cassert> #include <iomanip> // 用于 std::setprecision using std::cout; using std::endl; // 类Matrix的实现 class Matrix { public: Matrix(int n, int m); // 构造函数,构造一个n*m的矩阵, 初始值为0 Matrix(int n); // 构造函数,构造一个n*n的矩阵, 初始值为0 Matrix(const Matrix& x); // 复制构造函数,使用已有的矩阵X构造 ~Matrix(); // 析构函数 void set(const double* pvalue); // 用pvalue指向的连续内存块数据按行为矩阵赋值 void clear(); // 把矩阵对象的值置0 const double& at(int i, int j) const; // 返回矩阵对象索引(i,j)的元素const引用 double& at(int i, int j); // 返回矩阵对象索引(i,j)的元素引用 int get_lines() const; // 返回矩阵对象行数 int get_cols() const; // 返回矩阵对象列数 void display() const; // 按行显示矩阵对象元素值 private: int lines; // 矩阵对象内元素行数 int cols; // 矩阵对象内元素列数 double* ptr; // 指向矩阵数据的指针 }; // 构造函数(n x m 矩阵) Matrix::Matrix(int n, int m) : lines(n), cols(m) { ptr = new double[lines * cols](); // 初始化为0 } // 构造函数(n x n 矩阵) Matrix::Matrix(int n) : Matrix(n, n) {} // 复制构造函数 Matrix::Matrix(const Matrix& x) : lines(x.lines), cols(x.cols) { ptr = new double[lines * cols]; for (int i = 0; i < lines * cols; ++i) { ptr[i] = x.ptr[i]; // 深复制数据 } } // 析构函数 Matrix::~Matrix() { delete[] ptr; // 释放分配的内存 } // 设置矩阵数据 void Matrix::set(const double* pvalue) { for (int i = 0; i < lines * cols; ++i) { ptr[i] = pvalue[i]; } } // 清空矩阵 void Matrix::clear() { for (int i = 0; i < lines * cols; ++i) { ptr[i] = 0.0; } } // 获取元素的 const 引用 const double& Matrix::at(int i, int j) const { assert(i >= 0 && i < lines && j >= 0 && j < cols); // 边界检查 return ptr[i * cols + j]; // 计算并返回元素 } // 获取元素的引用 double& Matrix::at(int i, int j) { assert(i >= 0 && i < lines && j >= 0 && j < cols); // 边界检查 return ptr[i * cols + j]; // 计算并返回元素 } // 返回行数 int Matrix::get_lines() const { return lines; } // 返回列数 int Matrix::get_cols() const { return cols; } // 显示矩阵 void Matrix::display() const { for (int i = 0; i < lines; ++i) { for (int j = 0; j < cols; ++j) { cout << std::setw(1) << at(i, j) << " "; // 格式化输出 } cout << endl; } }
task4.cpp:
#include "matrix.hpp" #include <iostream> #include <cassert> using std::cin; using std::cout; using std::endl; const int N = 1000; // 输出矩阵对象索引为index所在行的所有元素 void output(const Matrix& m, int index) { assert(index >= 0 && index < m.get_lines()); for (auto j = 0; j < m.get_cols(); ++j) cout << m.at(index, j) << ", "; cout << "\b\b \n"; } void test1() { double x[1000] = { 1, 2, 3, 4, 5, 6, 7, 8, 9 }; int n, m; cout << "Enter n and m: "; cin >> n >> m; Matrix m1(n, m); // 创建矩阵对象m1, 大小n×m m1.set(x); // 用一维数组x的值按行为矩阵m1赋值 Matrix m2(m, n); // 创建矩阵对象m1, 大小m×n m2.set(x); // 用一维数组x的值按行为矩阵m1赋值 Matrix m3(2); // 创建一个2×2矩阵对象 m3.set(x); // 用一维数组x的值按行为矩阵m4赋值 cout << "矩阵对象m1: \n"; m1.display(); cout << endl; cout << "矩阵对象m2: \n"; m2.display(); cout << endl; cout << "矩阵对象m3: \n"; m3.display(); cout << endl; } void test2() { Matrix m1(2, 3); m1.clear(); const Matrix m2(m1); m1.at(0, 0) = -999; cout << "m1.at(0, 0) = " << m1.at(0, 0) << endl; cout << "m2.at(0, 0) = " << m2.at(0, 0) << endl; cout << "矩阵对象m1第0行: "; output(m1, 0); cout << "矩阵对象m2第0行: "; output(m2, 0); } int main() { cout << "测试1: \n"; test1(); cout << "测试2: \n"; test2(); }
实验结果截图:
任务五:
user.hpp:
#pragma once #include <iostream> #include <string> #include <regex> // 用于正则表达式 using std::string; class User { private: string name; string password; string email; public: // 构造函数,默认密码和邮箱 User(const string& userName, const string& pass = "123456", const string& userEmail = "") : name(userName), password(pass), email(userEmail) { } // 设置邮箱方法 void set_email() { string inputEmail; std::regex emailRegex(R"(^[^\s@]+@[^\s@]+\.[^\s@]+$)"); // 简单的邮箱格式检查 do { std::cout << "Enter your email: "; std::getline(std::cin, inputEmail); if (!std::regex_match(inputEmail, emailRegex)) { std::cout << "Invalid email format. Please try again." << std::endl; } } while (!std::regex_match(inputEmail, emailRegex)); email = inputEmail; // 赋值 } // 修改密码方法 void change_password() { string oldPassword; const int maxAttempts = 3; int attempts = 0; while (attempts < maxAttempts) { std::cout << "Enter your old password: "; std::getline(std::cin, oldPassword); if (oldPassword == password) { string newPassword; std::cout << "Enter your new password: "; std::getline(std::cin, newPassword); password = newPassword; // 更新密码 std::cout << "Password changed successfully." << std::endl; return; } else { std::cout << "Incorrect password. Try again." << std::endl; attempts++; } } std::cout << "Too many failed attempts. Please try again later." << std::endl; } // 显示用户信息 void display() const { std::cout << "User Name: " << name << "\n" << "Password: " << std::string(password.length(), '*') << "\n" << "Email: " << email << std::endl; } };
task5.cpp:
#include "user.hpp" #include <iostream> #include <vector> #include <string> using std::cin; using std::cout; using std::endl; using std::vector; using std::string; void test() { vector<User> user_lst; User u1("Alice", "2024113", "[email protected]"); user_lst.push_back(u1); cout << endl; User u2("Bob"); u2.set_email(); u2.change_password(); user_lst.push_back(u2); cout << endl; User u3("Hellen"); u3.set_email(); u3.change_password(); user_lst.push_back(u3); cout << endl; cout << "There are " << user_lst.size() << " users. they are: " << endl; for (auto& i : user_lst) { i.display(); cout << endl; } } int main() { test(); }
实验结果截图:
任务六:
date.h:
#ifndef __DATE_H__ #define __DATE_H__ class Date { private: int year; int month; int day; int totalDays; public: Date(int year, int month, int day); int getYear()const{ return year;} int getMonth()const{ return month;} int getDay()const{ return day;} int getMaxDay()const; bool isLeapYear()const{ return year%4==0&&year%100!=0||year%400==0; } void show()const; int distance(const Date& date)const { return totalDays - date.totalDays; } }; #endif // __DATE_H__
date.cpp:
#include"date.h" #include<iostream> #include<cstdlib> using namespace std; namespace { const int DAYS_BEFORE_MONTH[] = {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365}; } Date::Date(int year, int month, int day) :year(year),month(month),day(day) { if(day<=0||day>getMaxDay()){ cout << "Invalid date!"; show(); cout << endl; exit(1); } int years=year-1; totalDays=years*365+years/4-years/100+years/400+DAYS_BEFORE_MONTH[month-1]+day; if(isLeapYear()&&month>2) totalDays++; } int Date::getMaxDay() const { if(isLeapYear()&&month==2) return 29; else return DAYS_BEFORE_MONTH[month]-DAYS_BEFORE_MONTH[month-1]; } void Date::show() const { cout << getYear()<<"-"<<getMonth()<<"-"<<getDay(); }
account.h:
#ifndef ACCOUNT_H #define ACCOUNT_H #include "date.h" #include <string> class SavingsAccount { private: // 储蓄账户类 std::string id; double balance; // 账号 double rate; // 余额 Date lastDate; // 存款的年利率 double accumulation; // 上次变更余额的时期 static double total; // 余额按日累加之和 // 所有账户的总金额 // 记录一笔账, date为日期, amount为金额, desc为说明 void record(const Date& date, double amount, const std::string& desc); // 报告错误信息 void error(const std::string& msg) const; // 获得到指定日期为止的存款金额按日累积值 double accumulate(const Date& date) const { return accumulation + balance * date.distance(lastDate); } public: // 构造函数 SavingsAccount(const Date& date, const std::string& id, double rate); const std::string& getId() const { return id; } double getBalance() const { return balance; } double getRate() const { return rate; } static double getTotal() { return total; } // 存入现金 void deposit(const Date& date, double amount, const std::string& desc); // 取出现金 void withdraw(const Date& date, double amount, const std::string& desc); // 结算利息, 每年1月1日调用一次该函数 void settle(const Date& date); // 打印账户信息 void show() const; }; #endif // ACCOUNT_H
account.cpp:
// account.cpp #include "account.h" #include <cmath> #include <iostream> using namespace std; double SavingsAccount::total = 0; // SavingsAccount类相关成员函数的实现 SavingsAccount::SavingsAccount(const Date& date, const string& id, double rate) : id(id), balance(0), rate(rate), lastDate(date), accumulation(0) { date.show(); cout << "\t#" << id << " created" << endl; } void SavingsAccount::record(const Date& date, double amount, const string& desc) { accumulation = accumulate(date); lastDate = date; amount = floor(amount * 100 + 0.5) / 100; // 保留小数点后两位 balance += amount; total += amount; date.show(); cout << "\t#" << id << "\t" << amount << "\t" << balance << "\t" << desc << endl; } void SavingsAccount::error(const string& msg) const { cout << "Error(#" << id << "):" << msg << endl; } void SavingsAccount::deposit(const Date& date, double amount, const string& desc) { record(date, amount, desc); } void SavingsAccount::withdraw(const Date& date, double amount, const string& desc) { if (amount>getBalance()) { error("not enough money"); } else { record(date, -amount, desc); } } void SavingsAccount::settle(const Date& date) { double interest = accumulate(date) * rate; // 计算年息 date.distance(Date(date.getYear() - 1, 1, 1)); //这部分代码在给出的代码中被注释或省略了 if (interest != 0) { record(date, interest, " interest"); accumulation = 0; // 结算后清零 } } void SavingsAccount::show() const { cout << id << "\tbalance: " << balance; }
6_25.cpp:
// 6_25.cpp #include "account.h" #include <iostream> using namespace std; int main() { Date date(2008, 11, 1); SavingsAccount accounts[] = { SavingsAccount(date, "03755217", 0.015), SavingsAccount(date, "02342342", 0.015) }; const int n = sizeof(accounts) / sizeof(SavingsAccount); accounts[0].deposit(Date(2008, 11, 5), 5000, "salary"); accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323"); accounts[0].deposit(Date(2008, 12, 5), 5500, "salary"); accounts[1].withdraw(Date(2008, 12, 20), 4000, "buy a laptop"); cout << endl; for (int i = 0; i < n; i++) { accounts[i].settle(Date(2009, 1, 1)); accounts[i].show(); cout << endl; } cout << "Total: " << SavingsAccount::getTotal() << endl; return 0; }
实验结果截图:
标签:std,const,string,int,void,c++,实验,include From: https://www.cnblogs.com/gzry/p/18525739