task1.
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";
}#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();
}
问题一：自定义了两个类Button和Window,运用了标准库的类：vector、cout、string。Window类中包含了一个 vector<Button> 类型的成员变量buttons,因此Window类和Button类之间存在组合关系。
问题二：Button类中void click()修改了标准输出，不能改为const或设置为inline。Window类中void add_button(const string &label)可以设置为inline，其构造函数为简单函数。
问题三：string s(40, '*'); 输出40个“*”符号作为分隔线。
task2.
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();
}
问题1：先创建了一个名为v1的vector，包含5跟都是42的元素，然后创建一个名为v2的vector，并用v1来将其初始化，最后将v1的第一个元素改成了-999.
问题·2：第一行：初始化v1 相当于二维数组 第二行：v2为常量复制v1 第三行：将v1第一行中的最后一个改成-999
问题3：创建了一个名为t1的的vector，并用v1的第一个元素来将其初始化，然后输出t1的最后一个元素的值；创建了一个名为t2的vector，并用v2的第一个元素来将其初始化，然后输出t2的最后一个元素的值，并且因为t2前的const所以t2不能被修改
问题4:
1.深复制
2.需要
task3
task3.cpp
#include "vectorInt.hpp"
#include<iostream>
using std::cout;
using std::cin;
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();
}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;
};
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;
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;
}
问题1：深复制
问题2：不能将返回值类型改成int而非int&，由于at()现在返回的是值，因此无法通过返回的值来修改原始容器中的元素。
如果把line18返回值类型前面的const删掉，则不能修改任何成员变量。 问题3：不能。assign()返回值而不是引用,无法连续调用多个返回引用的成员函数。task.4
matrix.hpp
#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();
}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();
}
task5
user.cpp
1 #pragma once
2 #include <iostream>
3 #include <string>
4 #include <vector>
5
6 using std::string;
7 using std::cout;
8 using std::endl;
9 using std::vector;
10
11 class User {
12 public:
13 User(const string& name, const string& password = "123456", const string& email = "");
14 void set_email();
15 void change_password();
16 void display();
17 private:
18 string name;
19 string password;
20 string email;
21 };
22
23 User::User(const string& name, const string& password, const string& email) : name{ name }, password{ password }, email{ email } {}
24
25 void User::set_email() {
26 string input;
27 bool c = false;
28 cout << "Enter email address: ";
29 do {
30
31 std::cin >> input;
32 size_t pos = input.find('@');
33 if (pos != string::npos) {
34 c = true;
35 }
36 else {
37 cout << "illegal email. Please re-enter email: ";
38 }
39 } while (!c);
40 email = input;
41 cout << "email is set successfully..." << endl;
42 }
43
44 void User::change_password() {
45 string old_password;
46 string new_password;
47 int cnt = 0;
48 bool correct = false;
49 cout << "Enter old password: ";
50 do {
51
52 std::cin >> old_password;
53 if (old_password == password) {
54 correct = true;
55 }
56 else {
57 cnt++;
58 if (cnt == 3) {
59 cout << "password input error. Please try after a while." << endl;
60 return;
61 }
62 cout << "password input error. Please re-enter again: ";
63 }
64 } while (!correct);
65 cout << "Enter new password: ";
66 std::cin >> new_password;
67 password = new_password;
68 cout << "new password is set successfully..." << endl;
69 }
70
71 void User::display() {
72 cout << "name: " << name << endl;
73 string showpassword(password.length(), '*');
74 cout << "pass: " << showpassword << endl;
75 cout << "email: " << email << endl;
76 }
user.cpptask5.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();
}
task6
date.h
#ifndef __DATE_H__
#define __DATE_H__
class Date {//日期类
private:
int year; //年
int month;//月
int day;//日
int totalDays;//该日期是从公元元年1月1日开始的第几天
public:
Date(int year, int month, int day);//用年、月、日构造日期
int getYear() const { return year; }
int getMonth() const { return month; }
int getDay() const { return day; }
int getMaxDay() const;//获得当月有多少天
bool isLeapYear() const {//判断当年是否为闰年
return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
}
void show() const;//输出当前日期
int distance(const Date & date) const {
return totalDays - date.totalDays;
}
};
#endif //__DATE_H__date.cpp
//date.cpp
#include "date.h"
#include <iostream>
#include <cstdlib>
using namespace std;
namespace {
//namespace使下面的定义只在当前文件中有效
const int DAYS_BEFORE_MONTH[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 356 };
}
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
//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;//按日累加以和
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;
//获得指定日期为止的存款金额按日累增值
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);//获得账号
const std::string & getId() const { return id; } //获得余额
double getBalance() const { return balance; } //获得年利率
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__#pragma onceaccount.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 / date.distance(Date(date.getYear() - 1, 1, 1));
if (interest != 0)
record(date, interest, "interest");
accumulation = 0;
}
void SavingsAccount::show() const {
cout << "ID: " << id << "\tBalance: " << balance;
}task6.cpp
//6.25.cpp
#include "account.h"
#include <iostream>
using namespace std;
int main() {
Date date(2008, 11, 1);
//起始日期
//建立几个账户
SavingsAccount accounts[] = {
SavingsAccount(date, "03755217", 0.015),
SavingsAccount(date, "02342342", 0.015)
};
//几笔账目
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");
//结算所有账户并输出各个账户信息
cout << endl;
for (int i = 0; i < sizeof(accounts) / sizeof(SavingsAccount); i++) {
accounts[i].settle(Date(2009, 1, 1));
accounts[i].show();
cout << endl;
}
cout << "Total: " << SavingsAccount::getTotal() << endl;
return 0;
}