实验三

任务一

button.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";
}

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));
}

task.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();
}

问题1:自定义了2个类,window和button。使用了string和vector(标准库)

问题2:剩余的函数有close(),add_button,他们主要是用来输出,因此不会改变函数内对象的值。

问题3:定义s,s由四十个*组成

任务二

#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();
}

输出结果

 问题一:第一行创造一个长度为五,全为42的整型vector对象v1。第二行创造一个与v1一样的对象v2。第三行将v1的第一个值改为-999。

问题二:第一行创造一个vector对象v1,它的元素为整型vector类。第二行创造一个与v2一样的对象v2。第三行在v1第一个元素内插入-999。

问题三:第一行将v1的第一个集合复制给t1。第二行输出集合t1的最后一个值。第三行将v2的第一个集合复制给t2。第四行输出集合t2的最后一个值。

问题四:vector内部封装的复制构造函数,其实现机制是深复制。 模板类vector的接口at(), 需要提供一个const成员函数作为接口。

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

 问题一:line14是深复制

问题二:返回值类型改成int而非int&,不能正确运行。存在安全隐患,去掉const导致at函数中的返回值有可能被改变,存在隐患。

问题三:assign()接口,返回值类型 不可以改成vectorInt,因为return *this是返回当前对象或复制体的意思。修改后每次调用都会产生一个新的对象。

任务四

matrix.hpp

 

#pragma once

#include <cassert>
#include <iostream>

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:待补足
// xxx
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 < cols * lines; i++)
  {
    ptr[i] = pvalue[i];
  }
}
void Matrix::clear()
{
  for (int i = 0; i < cols * lines; i++)
  {
    ptr[i] = 0;
  }
}
const double &Matrix::at(int i, int j) const
{
  return ptr[i * cols + j];
}
double &Matrix::at(int i, int j)
{
  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 << ptr[i * cols + j] << ", ";
    }
    cout << "\b\b \n";
  }
}

task4.cpp

#include "matrix.hpp"
#include <cassert>
#include <iostream>

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

任务五

user.hpp

#pragma once

#include <cassert>
#include <iostream>
#include <string>

using namespace std;
class User
{
public:
  User(const string name, string password = "123456", string email = "");
  void set_email();
  void change_password();
  void display() const;

private:
  string name;
  string password;
  string email;
};
void User::set_email()
{
  cout << "Enter email address:";
  string emailname;
  cin >> emailname;
  while (1)
  {
    if (emailname.find('@') == string::npos)
    {
      cout << "illegal email.Please re-enter email:";
      cin >> emailname;
    }
    else
    {
      email = emailname;
      cout << "email is set sucessfully..." << endl;
      break;
    }
  }
}
void User::change_password()
{
  cout << "Enter old password: ";
  string oldpassword;
  string newpassword;
  cin >> oldpassword;
  int h = 0;
  while (h < 2)
  {
    if (password == oldpassword)
    {
      cout << "Enter newpassword:";

      cin >> newpassword;
      password = newpassword;
      cout << "new password is set sucessfully..." << endl;
      break;
    }
    else
    {
      cout << "password input error.Please re-enter again: ";
      cin >> oldpassword;
      h++;
    }
  }
  if (h == 2)
    cout << "password input error.Please try after a while" << endl;
}
void User::display() const
{
  cout << "name:   " << name << endl;
  cout << "pass:   ";
  for (int i = 0; i < password.length(); i++)
    cout << "*";
  cout << endl;
  cout << "email:  " << email << endl;
}

task5.cpp

#include "user.hpp"
#include <iostream>
#include <string>
#include <vector>

using std::cin;
using std::cout;
using std::endl;
using std::string;
using std::vector;

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();
}

实验结果

任务6

account.h

#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
#include "date.h"
#include <string>
class SavingsAccount {
    //储蓄账户类
private:
    std::string id;
    //账号
    double balance;
    //余额
    double rate;
    //存款的年利率
    Date lastDate;
    //上次变更余额的时期
    double accumulation;
    //余额按日累加之和
    static double total;
    //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.dístance(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);
    //显示账户信息
    void show() const;
};
#endif//__ACCOUNT_H__

account.cpp

#include"account.h"
#include<cmath>
#include<iostream>
using namespace std;
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;
}

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;
    }
};

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();
}

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;
}

 

posted @ 2024-11-10 20:31  孟潇辉  阅读(4)  评论(0编辑  收藏  举报