test1:
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();
}
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));
}
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";
}
运行结果：
问题1：
自定义两个类，用到了标准库三个类，Window 和Button有组合关系
2：
1.click函数
1.答案：不适合加const和inline。
2.理由：逻辑上表示按钮状态改变，与可变行为相关，不适合const；涉及cout输出，相对复杂，内联可能导致代码膨胀。
2.close函数
1.答案：适合加const，不适合inline。
2.理由：未修改对象内部状态，加const可提高可读性；涉及cout输出和调用其他函数，内联会致代码膨胀。
3.add_button函数
1.答案：不适合加const和inline。
2.理由：修改成员变量，不符合const；向向量添加元素复杂，inline可能致代码膨胀。
3：
声明s是长度为40的字符串，并将每个字符赋值为*
test2:
#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();
}
运行结果：
问题1.
为v1申请一片储存整型变量的空间并赋值5，42；
为v2申请一片储存整型变量的空间并将v1中的元素赋值给v2；
将v1中的第一个元素赋值为-999；
2.
为v1申请一片储存储存整型数据的空间的空间；
为v2申请一片储存储存整型数据的空间的空间并将v1中的元素赋值给v2；
在v1中第一个空间的末尾插入值为-999的整型元素；
3.
为t1一片储存整型数据的空间并将v1中第一个空间中的的元素赋值给v2；
输出t1中最后一个元素的值并换行；
为t2一片储存整型数据的空间并将v2中第一个空间中的的元素赋值给v2，并且声明t2不可被修改；
输出t2中最后一个元素的值并换行；
test3:
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();
}
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;
}
运行结果：
问题1.
浅复制
2.
不能正常运行，返回值不可以改成int类型，测试1中对返回值进行了赋值操作。
有安全隐患，测试可能有改变返回值的操作
3.
可以
test4:
matrix.hpp：
#pragma once
#include <iostream>
#include <cassert>
#include <vector>
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 [lines * cols];
}
Matrix::Matrix(int n) :lines{ n }, cols{ n } {
ptr = new double[lines * cols];
}
Matrix::Matrix(const Matrix& x) :lines{ x.lines }, cols{ x.cols } {
ptr = new double[lines * cols];
for (auto i = 0; i < lines; i++)
for (auto j = 0; j < cols; j++)
ptr[i * cols + j] = x.at(i, j);
}
Matrix::~Matrix() { delete[]ptr; lines = 0; cols = 0; }
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; i++)
for (int j = 0; j < cols; j++)
ptr[i * cols + j] = 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 << 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();
}
运行结果：
test5:
user.hpp：
#pragma once
#include <iostream>
#include <cassert>
#include <string>
using std::cin;
using std::cout;
using std::endl;
class User {
public:
User(std::string n, std::string p = "123456", std::string e = "") :name{ n }, password{ p }, email{ e } {};
~User()=default;
void set_email();
void change_password();
void display() const;
private:
std::string name;
std::string password;
std::string email;
};
void User::set_email() {
std::string t;
cout << "Please enter the email:";
cin >> t;
auto i = std::find(t.begin(), t.end(), '@');
if (i != t.end()) { email = t; cout << "OK" << endl; }
else cout << "ERROR" << endl;
}
void User::change_password() {
std::string t;
cout << "Please enter the old password:";
for (int i = 0; i < 3; i++)
{
cin >> t;
if (t == password) {
cout << "Right,please enter the new password:";
cin >> password;
cout << "OK;";
break;
}
else if (i < 2) cout << "Wrong,please try again:";
else cout << "Wrong,please try after afew minute.";
}
}
void User::display() const{
cout << "Name:" << name << endl;
cout << "Email:" << email << endl;
cout << "Password:";
for (int i = 0; i < password.length(); i++)
{
cout << '*';
}
cout << 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();
}
运行结果：
test6:
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;
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.dístance(Date(date.getYear() - 1, 1, 1));
if (interest != 0)
record(date, interest, "interest");
accumulation = 0;
}
void SavingsAccount::show() const {
cout << id << "\tBalance:" << balance;
}
data.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日开始的第儿天
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
//计算两个日期之间差多少天
int dístance(const Date& date) const {
return totalDays - date.totalDays;
}
};
#endif / / _DATE_H__
data.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
//存储平年中的某个月1日之前有多少天，为便于getMaxDay函数的实现，该数组多出一项
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() {
//起始日期
Date date(2008, 11, 1);
//建立几个账户
SavingsAccount accounts[] = {
SavingsAccount(date,"03755217",0.015),
SavingsAccount(date, "02342342", 0.015)
};
const int n = sizeof(accounts) / sizeof(SavingsAccount); //账户总数
//11月份的几笔账目
accounts[0].deposit(Date(2008, 11, 5), 5000, "salary");
accounts[1].deposit(Date(2008, 11, 25), 10000, "sell stock 0323");
//12月份的几笔账目
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 < n; 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,void,编程,int,实验,include From： https://www.cnblogs.com/the-existent/p/18531196