实验3 类和对象_基础编程2
实验任务1
bottom.hpp
#pragma once
#include <iostream>
#include <string>
using std::string;
using std::cout;
// 按钮类
class Button {
public:
Button(const string &text);
string get_label() const;
void click();
private:
string label;
};
Button::Button(const string &text): label{text} {
}
inline string Button::get_label() const {
return label;
}
void Button::click() {
cout << "Button '" << label << "' clicked\n";
}
windows.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();
}
运行测试结果截图：
问题1：自定义两个类：分别是button类和window类；
使用标准库类：iostream类、string类和vector类；
组合关系：Window 类中包含了 vector<Button>，表示窗口中有多个按钮。
Window 类的构造函数中创建了一个 Button对象，用于将给定的短语添加到类中定义的成员中。
问题2：不合适。因为没有加const是为了方便修改内部的数据，不加inline是表示成员函数并不要多次调用，没有必要，加了反而会报错。
问题3：用40个*来分隔板块，实现虚拟的窗口。
实验内容2
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();
}
运行测试结果截图：
问题1：line21的功能是创建一个动态数组v1，存放整型类型数据，将5个42存放在v1中
line22的功能是复制v1
line24的功能是修改v1中索引为0的值改为-999
问题2：line32的功能是创建一个动态二维数组v1，存放整型数据，并初始化
line33的功能是创建一个常量动态二维数组v2，将v1的值复制给v2，且不能修改值
line35的功能是修改v1中索引为0的值改为-999
问题3：line39的功能是创建动态数组t1并将v1中索引为0的值赋值给t1
line40的功能是打印t1中的最后一个元素
line42的功能是创建常量动态数组t2并将v2中索引为0的值赋值给t2
line43的功能是打印t2中的最后一个元素
问题4：1）深复制
2）需要，否则用户无法使用const vector调用该方法
实验任务3
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();
}
运行测试结果截图：
问题1：深复制
问题2：不能，返回类型变成int的话代表不能被修改；去掉const，会存在安全隐患，因为成员函数内部数据可能会被修改
问题3：可以，如果将其改为 vectorInt，仍然可以实现类似的功能。在使用 assign () 函数进行赋值操作时，无论是返回引用还是返回一个新的对象，都可以在赋值语句中进行链式操作或者连续赋值
实验任务4
Matrix.hpp
#pragma once
#include <iostream>
#include <cassert>
using std::cout;
using std::endl;
// 类Matrix的声明
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value
Matrix(int n); // 构造函数，构造一个n*n的矩阵, 初始值为value
Matrix(const Matrix &x); // 复制构造函数， 使用已有的矩阵X构造
~Matrix();
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;
};
// 类Matrix的实现
Matrix::Matrix(int n, int m) : lines(n), cols(m) {
ptr = new double[n * m];
}
Matrix::Matrix(int n) : lines(n), cols(n) {
ptr = new double[n * n];
}
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];
}
}
Matrix::~Matrix() {
delete[] ptr;
}
void Matrix::set(const double *pvalue) {
for (int i = 0; i < lines * cols; ++i) {
ptr[i] = *(pvalue + i);
}
}
void Matrix::clear() {
for (int i = 0; i < lines * cols; ++i) {
ptr[i] = 0;
}
}
const double& Matrix::at(int i, int j) const {
assert(i >= 0 && i < lines && j >= 0 && j < cols);
return ptr[i * cols + j];
}
double& Matrix::at(int i, int j) {
assert(i >= 0 && i < lines && j >= 0 && j < cols);
return ptr[i * cols + j];
}
int Matrix::get_lines() const {
return lines;
}
int Matrix::get_cols() const {
return cols;
}
void Matrix::display() const {
for (int i = 0; i < lines; ++i) {
for (int j = 0; j < cols; ++j) {
cout << at(i, j) << " ";
}
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] = {0, 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();
}
运行测试结果截图：
实验任务5
User.hpp
#include <iostream>
#include <string>
#include <iomanip>
class User {
private:
std::string name;
std::string password;
std::string email;
public:
User(const std::string& name, const std::string& password = "123456", const std::string& email = "")
: name(name), password(password), email(email) {}
void set_email() {
std::string input;
std::cout << "Enter email address: ";
while (true) {
std::cin >> input;
if (input.find('@') != std::string::npos) {
email = input;
std::cout << "email is set successfully...\n";
break;
} else {
std::cout << "illegal email. Please re-enter email:";
}
}
}
void change_password() {
const int max_attempts = 3;
int attempts = 0;
std::string old_password;
std::cout << "Enter old password: ";
while (attempts < max_attempts) {
std::cin >> old_password;
if (old_password == password) {
std::string new_password;
std::cout << "Enter new password: ";
std::cin >> new_password;
password = new_password;
std::cout << "new password is set successfully...\n";
return;
} else {
attempts++;
if(attempts != 3){
std::cout << "password input error. Please re-enter again:";
}
}
}
std::cout << "password input error. Please try after a while\n";
}
void display() const {
std::cout << "name: " << name << "\n";
std::cout << "pass: ";
for (char ch : password) {
std::cout << '*';
}
std::cout << "\n";
std::cout << "email: " << email << "\n";
}
};
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", "Alice@hotmail.com");
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();
}
运行测试结果截图：
实验任务6
date.h
processing
#pragma once
#include<iostream>
#include<cstdlib>
using namespace std;
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;
}
};
namespace {
const int DAYS_BEFIRE_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_BEFIRE_MONTH[month - 1] + day;
if (isLeapYear() && month > 2) totalDays++;
}
int Date::getMaxDay()const {
if (isLeapYear() &&month == 2)
return 29;
else return DAYS_BEFIRE_MONTH[month] - DAYS_BEFIRE_MONTH[month - 1];
}
void Date::show()const {
cout << getYear() << "-" << getMonth() << "-" << getDay();
}
account.hpp
cpp
#pragma once
#include"date.hpp"
#include<string>
#include<cmath>
#include<iostream>
using namespace std;
class SavingsAccount {
private:
string id;
double balance;
double rate;
Date lastDate;
double accumulation;
static double total;
void record(const Date& date, double amount, const string& desc);
void error(const string& msg) const;
double accumulate(const Date& date)const {
return accumulation + balance * date.distance(lastDate);
}
public:
SavingsAccount(const Date& date, const string& id, double rate);
const string& getId()const {
return id;
}
double getBalance()const {
return balance;
}
double getRate()const {
return rate;
}
static double getTotal() {
return total;
}
void deposit(const Date& date, double amount, const string& desc);
void withdraw(const Date& date, double amount, const string& desc);
void settle(const Date& date);
void show() const;
};
double SavingsAccount::total = 0;
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;
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 / date.distance(Date(date.getYear() - 1, 1, 1));
if (interest != 0) record( date,interest,"interest" );
accumulation = 0;
}
void SavingsAccount::show()const {
cout << id << "\tBalance: " << balance;
}
task6.cpp
cpp
#include"account.hpp"
#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;
}
运行测试结果截图：
