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));
}
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1：自定义了两个类，Window和Button。使用了标准库的两个类vector和string。Button中使用string，Window中使用string，vector和Button。
问题2：不适合。const是表示数据不可更改，随意添加可能会报错。inline是修饰内联，小且多次调用的函数加上inline可以提高效率，否则无法提高效率还会增加开销。
问题3：输出40个*号，让输出结果更清晰。
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();
}
问题1：21行：创建一个包含5个元素的int型数组v1，且每个元素初始值为42.
22行：将v1的数组复制到v2的数组中。
23行：将v1的第一个元素赋值为-999。
问题2：32行：创建了一个二维int型数组v1，包含两个一维数组，分别为{1，2，3}和{4，5，6，7}。
33行：将v1的数组复制到v2中，且v2的值不可改变。
34行：在v1的第一行的最后插入-999。
问题3：39行：将v1中地址为0的数组赋值t1。
40行：输出t1中的最后一个元素。
42行：将v2中地址为0的数组赋值给t2。
43行：输出t2中的最后一个元素。
问题4：深复制。需要。
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();
}
问题1：深复制
问题2：不能正确运行，左操作数必须为左值。存在安全隐患。
问题3：可以，但会占用额外内存。
任务4：
Matrix.h:
#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：待补足
// xxx
Matrix.cpp:
#include <iostream>
#include "Matrix.h"
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];
std::copy(x.ptr, x.ptr + lines * cols, ptr);
}
Matrix::~Matrix() {
delete[] ptr;
}
void Matrix::set(const double *pvalue) {
std::copy(pvalue, pvalue + lines * cols, ptr);
}
void Matrix::clear() {
std::fill(ptr, ptr + lines * cols, 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 << ptr[i * cols + j] << " ";
}
cout << endl;
}
}
task4.cpp:
#include "Matrix.h"
#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();
}
任务5：
user.hpp
#ifndef USER_HPP
#define USER_HPP
#include <iostream>
#include <string>
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;
do {
std::cout << "Enter email address: ";
std::cin >> input;
if (input.find('@') != std::string::npos) {
email = input;
std::cout << "email is set successfully..." << std::endl;
} else {
std::cout << "illegal email. Please re-enter email.";
}
} while (input.find('@') == std::string::npos);
}
void change_password() {
std::string old_password;
int attempts = 0;
while (attempts < 3) {
std::cout << "Enter old password: ";
std::cin >> old_password;
if (old_password == password) {
std::string new_password;
std::cout << "Enter new password: ";
std::cin >> new_password;
std::cout << "new password is set successfully..." << std::endl;
password = new_password;
return;
} else {
attempts++;
if (attempts < 3) {
std::cout << "password input error. Please re-enter angain.";
}
else{
std::cout << "password input error. Please try after a while." << std::endl;
}
}
}
}
void display() const {
std::cout << "\nUsername: " << name << "\npass: " << std::string(password.length(), '*') << "\nemail: " << email << std::endl;
}
};
#endif
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();
}
任务6：
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.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, 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
#ifndef __ACCOUNT_H__
#define __ACCOUNT_H__
#include "date.h"
#include <string>
class SavingsAccount {
private:
std::string id;
double balance;
double rate;
Date lastDate;
double accumulation;
static double total;
void record(const Date & date, double amount, const std::string & desc);
void error(const std::string & msg) const;
double accumulate(const Date & date) const {
return accumulation + balance * date.distance(lastDate);
}
public:
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; }
void deposit(const Date & date, double amount, const std::string & desc);
void withdraw(const Date & date, double amount, const std::string & desc);
void settle(const Date & date);
void show() const;
};
#endif
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: " << id << "\tBalance: " << balance;
}
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)
};
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 < sizeof(accounts) / sizeof(SavingsAccount); i++) {
accounts[i].settle(Date(2009, 1, 1));
accounts[i].show();
cout << endl;
}
cout << "Total: " << SavingsAccount::getTotal() << endl;
return 0;
}
标签：std,const,cout,对象,编程,int,实验,include,string From： https://www.cnblogs.com/luyiming/p/18525637