[C++知识库]C++ 图书馆管理系统

此管理系统相比于上一篇用Java实现的功能更多了，结构更加简单了，没有用继承之类的复杂语法。逻辑实现上更加严谨了，但是并没有异常处理，以及文件读取等持久化信息的操作，这些操作需要后续的学习。

功能概览

?

Library.h

BookRecord

#include<vector>
#include<cassert>
#include<string>
#include<iostream>
#include<map>
#include<set>
using namespace std;

// 图书类
class BookRecord
{
public:
	BookRecord(string s1, string s2, string s3, string s4, unsigned int n1, unsigned int n2) :
		book_title_(s1), book_isbn_(s2), author_(s3), year_published_(s4), number_of_copies_(n1), number_of_copies_available_(n2) {}
	~BookRecord() = default;

	void DisplayRecord()const;  // 打印
	bool loan_out();       // 书籍借出函数
	void AddBook(int n) { number_of_copies_ += n; number_of_copies_available_ += n; } // 增添书籍
	bool is_available()const { return number_of_copies_available_ > 0; }     // 判断是否有余量。
	bool deletebook()const { return number_of_copies_ == number_of_copies_available_; }  // 删除书籍
	void ReturnBook() { ++number_of_copies_available_; }  // 归还书籍
	const string& isbn()const { return book_isbn_; }   // 返回ISBN
	const string& name()const { return book_title_; }  // 返回名字

private:
	string book_title_;
	string book_isbn_;
	string author_;
	string year_published_;
	unsigned int number_of_copies_;
	unsigned int number_of_copies_available_;
};

存储图书的基本信息，以及一些对外接口。?

Borrower

// 借阅人类
class Borrower
{
public:
	Borrower(string id, string name, string tele)
		:borrower_id_(id), name_(name), telephone_(tele){}
	~Borrower() = default;

	const string& id()const { return borrower_id_; }
	const string& name()const { return name_; }

	void DisplayRecord()const;		  // 打印函数
	void LoanBook(const string& s);		// 借书
	bool ReturnBook(const string& s);   // 还书
	bool Logout()const { return book_loaned_ == 0; }   // 注销
private:
	string borrower_id_;
	string name_;
	string telephone_;
	unsigned int book_loaned_ = 0;
	vector<string> book_loaned_titles_ = vector<string>();
};

借阅人类，存储借阅人的基本信息，其中包括这个人借了哪些书，vector存储那些书籍的书名。?

Library

// 图书馆类
class Library
{
public:
	Library() = default;
	~Library()
    {
		for (const auto& i : vec_pbook_)
			delete i;
		for (const auto& i : vec_pborrower_)
			delete i;
	}
	Library(const Library&) = delete;
	Library& operator=(const Library&) = delete;

	void DisplayAllBook()const;   // 打印全部书籍
	void DisplayAllBorrower()const;  // 打印全部借阅人
	void DisplayBook()const;	// 打印特定书籍
	void DisplayBorrower()const;	// 打印特定借阅人

	void AddBook();		// 添加书籍
	void DeleteBook();	// 删除书籍
	
	void LoanBook();	// 借书
	void ReturnBook();	// 还书

	void Register();	// 注册
	void Logout();		// 注销

private:
	vector<Borrower*> vec_pborrower_;
	vector<BookRecord*> vec_pbook_;

	map<string, Borrower*> map_borrower_;      // 书籍的ISBN映射到书籍对象指针
	map<string, BookRecord*> map_bookrecord_;  // 借阅人id到借阅人对象指针的映射
};

数据成员有 借阅人对象指针的vector 和 书籍对象指针的vector。这里方便遍历。? 还有借阅人id到对象指针的map映射，方便通过id检索此人是否存在，以及对应对象的方法调用。?还有书籍isbn到书籍对象指针的map映射，同样也是方便检索。

成员函数就是那些功能的实现，都封装在了一个Library类的对象中。main.cpp中可以看到调用。

Library.cpp

BookRecord成员函数实现

#include"Library.h"


void BookRecord::DisplayRecord()const
{
	auto c1 = book_title_.c_str(), c2 = book_isbn_.c_str(), c3 = author_.c_str(), c4 = year_published_.c_str();
	printf("书名:%-10s ISBN：%-15s 作者:%-8s 出版年: %-5s 总数量:%d 余量:%d\n", c1, c2, c3, c4, number_of_copies_, number_of_copies_available_);
}

bool BookRecord::loan_out()
{
	if (number_of_copies_available_ > 0)
	{
		--number_of_copies_available_;
		return true;
	}
	else
	{
		return false;
	}
}

loan_out 成员函数用于判断此书是否还有余量可以借出，用于LoanBook方法中。用返回值判断是否还有余量。?

Borrower成员函数实现

void Borrower::DisplayRecord()const
{
	auto c1 = borrower_id_.c_str(), c2 = name_.c_str(), c3 = telephone_.c_str();
	printf("ID:%-15s 姓名:%-5s 联系方式:%-15s 借阅书籍数量:%d\n", c1, c2, c3, book_loaned_);
	if (book_loaned_ != 0)
	{
		cout << "借阅书籍名称" << ": ";
		for (const auto& i : book_loaned_titles_)
			cout << i << "  ";
		cout << endl;
	}
}

void Borrower::LoanBook(const string& title)
{
	++book_loaned_;
	book_loaned_titles_.push_back(title);
}

bool Borrower::ReturnBook(const string& name)
{
	for (auto i = book_loaned_titles_.begin(); i != book_loaned_titles_.end(); ++i)
	{
		if ((*i) == name)
		{
			book_loaned_titles_.erase(i);
			--book_loaned_;
			return true;
		}
	}
	return false;
}

LoanBook用于辅助Library类的LoanBook的实现。ReturnBook需要将书籍名在对象的vector<string>中删除，还要将借书量减一。?

Library的打印函数实现

void Library::DisplayAllBook()const
{
	if (!vec_pbook_.empty())
		for (auto i : vec_pbook_)
			i->DisplayRecord();
	else
		cout << "图书馆暂无书籍" << endl;
}

void Library::DisplayAllBorrower()const
{
	if (!vec_pborrower_.empty())
		for (auto i : vec_pborrower_)
			i->DisplayRecord();
	else
		cout << "图书馆暂无借阅人" << endl;
}

void Library::DisplayBook()const
{
	cout << "请输入书籍名称" << endl;
	string name;
	cin >> name;
	for (const auto& i : vec_pbook_)
		if (i->name() == name)
		{
			i->DisplayRecord();
			return;
		}
	cout <<"错误，" << name << "书籍不存在" << endl;
}

void Library::DisplayBorrower()const
{
	cout << "请输入借阅人姓名" << endl;
	string name;
	cin >> name;
	for(const auto& i :vec_pborrower_)
		if (i->name() == name)
		{
			i->DisplayRecord();
			return;
		}
	cout << "错误" << name << "借阅人不存在" << endl;
}

略?

LoanBook + ReturnBook? 借书+还书

void Library::LoanBook()
{
	cout << "请输入你的id号码" << endl;
	string id;
	cin >> id;
	if (map_borrower_.find(id) == map_borrower_.end())
	{
		cout << "错误，你尚未注册，无法借书" << endl;
		cout << "是否注册？(Y/N)" << endl;
		char input = ' ';
		cin >> input;
		if (input == 'Y' || input == 'y')
			Register();
		return;
	}
	cout << "请输入你想借阅的书籍书名" << endl;
	string name;
	cin >> name;
	for (auto i = vec_pbook_.begin(); i != vec_pbook_.end(); ++i)
	{
		// 这里用到了vector_pbook
		if ((*i)->name() == name)
		{
			if ((*i)->loan_out())
			{
				map_borrower_[id]->LoanBook(name);
				cout << "借阅成功" << endl;
			}
			else
				cout << "书籍余量为零，借阅失败" << endl;
			return;
		}
	}
	cout << name << "书籍不存在" << endl;
}

void Library::ReturnBook()
{
	cout << "请输入你的id号码" << endl;
	string id;
	cin >> id;
	if (map_borrower_.find(id) == map_borrower_.end())
	{
		cout << "错误，你尚未注册，无法归还书籍" << endl;
		cout << "是否注册？(Y/N)" << endl;
		char input = ' ';
		cin >> input;
		if (input == 'Y' || input == 'y')
			Register();
		return;
	}
	cout << "请输入你要归还书籍的ISBN编号" << endl;
	string isbn;
	cin >> isbn;
	if (map_bookrecord_.find(isbn) == map_bookrecord_.end())
	{
		cout << "错误，图书馆不存在此书" << endl;
		return;
	}
	auto name = map_bookrecord_[isbn]->name();
	if (map_borrower_[id]->ReturnBook(name))
	{
		map_bookrecord_[isbn]->ReturnBook();
		return;
	}
	else
		cout << "错误，检测到你尚未借过此书" << endl;
}

逻辑较为缜密? ?借书和还书时，借阅人那里和书籍那里都要处理。?

AddBook + DeleteBook 添加书籍 删除书籍? 这是管理员的功能

void Library::AddBook()
{
	string title, isbn, author, published;
	unsigned int copies;
	cout << "请输入书名，ISBN编号，作者名，出版年，数量。中间以空格隔开" << endl;
	cin >> title >> isbn >> author >> published >> copies;
	if (map_bookrecord_.find(isbn) == map_bookrecord_.end())
	{
		BookRecord* p = new BookRecord(title, isbn, author, published, copies, copies);
		assert(p);
		vec_pbook_.push_back(p);
		map_bookrecord_.insert({ p->isbn(),p });
	}
	else
		map_bookrecord_[isbn]->AddBook(copies);
	cout << "添加成功" << endl;
}

void Library::DeleteBook()
{
	string isbn;
	cout << "请输入你要删除的书籍ISBN号码:>" << endl;
	cin >> isbn;
	if (map_bookrecord_.find(isbn) == map_bookrecord_.end())
	{
		cout << "错误，该书籍不存在!!!" << endl;
		return;
	}
	else if (map_bookrecord_[isbn]->deletebook() == false)
	{
		cout << "错误，此书籍尚未全部归还!!!" << endl;
		return;
	}
	auto p = map_bookrecord_[isbn];
	map_bookrecord_.erase(isbn);
	for (auto i = vec_pbook_.begin(); i != vec_pbook_.end(); ++i)
	{
		if (*i == p)
		{
			vec_pbook_.erase(i);
			break;
		}
	}
	delete p;
	cout << "删除成功" << endl;
}

?vector和map中都要处理信息。不过是书籍的vector和map

Register + Logout? 注册 注销 用于借阅人的操作

void Library::Register()
{
	string id;
	cout << "请输入一个你自己的id号码" << endl;
	do
	{
		cin >> id;
		if (map_borrower_.find(id) != map_borrower_.end())
		{
			cout << "错误，此id已存在，请重新输入。" << endl;
		}
		else
			break;
	} while (true);
	string name, tele;
	cout << "请输入你的姓名，联系方式" << endl;
	cin >> name >> tele;
	Borrower* p = new Borrower(id, name, tele);
	assert(p);
	vec_pborrower_.push_back(p);
	map_borrower_.insert({ id,p });
	cout << "注册成功" << endl;
}

void Library::Logout()
{
	cout << "请输入你的id号码" << endl;
	string id;
	cin >> id;
	if (map_borrower_.find(id) == map_borrower_.end())
	{
		cout << "错误，你尚未注册" << endl;
		cout << "是否注册？(Y/N)" << endl;
		char input = ' ';
		cin >> input;
		if (input == 'Y' || input == 'y')
			Register();
		return;
	}
	else if (map_borrower_[id]->Logout() != true)
	{
		cout << "错误，注销失败，你有书籍尚未归还" << endl;
		return;
	}
	auto p = map_borrower_[id];
	for (auto i = vec_pborrower_.begin(); i != vec_pborrower_.end(); ++i)
		if (*i == p)
		{
			vec_pborrower_.erase(i);
			break;
		}
	map_borrower_.erase(id);
	delete p;
	cout << "注销成功" << endl;
}

vector和map都要处理。? 借阅人的vector和map

Main.cpp

#include"Library.h"


void menu()
{
	cout << "       欢迎进入图书馆       " << endl;
	cout << "==========================" << endl;
	cout << "      1.  管理员系统       " << endl;
	cout << "      2.  借阅人系统       " << endl;
	cout << "      0.  退出系统         " << endl;
	cout << "==========================" << endl;
}

void MenuOfManager()
{
	cout << "       欢迎进入管理员系统       " << endl;
	cout << "==============================" << endl;
	cout << "      1.  查看全部书籍      " << endl;
	cout << "      2.  查看全部借阅人       " << endl;
	cout << "      3.  查找指定书籍       " << endl;
	cout << "      4.  查找指定借阅人       " << endl;
	cout << "      5.  添加书籍       " << endl;
	cout << "      6.  删除书籍       " << endl;
	cout << "      0.  退出系统        " << endl;
	cout << "=============================" << endl;
}

void MenuOfReader()
{
	cout << "       欢迎进入借阅人系统      *" << endl;
	cout << "==============================" << endl;
	cout << "      1.  查看全部书籍     " << endl;
	cout << "      2.  查找指定书籍      " << endl;
	cout << "      3.  借阅书籍    " << endl;
	cout << "      4.  归还书籍       " << endl;
	cout << "      5.  注册           " << endl;
	cout << "      6.  注销		  " << endl;
	cout << "      0.  退出系统        " << endl;
	cout << "==============================" << endl;
}

void manager(Library& lib)
{
	int input = 0;
	do
	{
		MenuOfManager();
		printf("请输入你的选择:>");
		cin >> input;
		switch (input)
		{
		case 1:
			lib.DisplayAllBook();
			break;
		case 2:
			lib.DisplayAllBorrower();
			break;
		case 3:
			lib.DisplayBook();
			break;
		case 4:
			lib.DisplayBorrower();
			break;
		case 5:
			lib.AddBook();
			break;
		case 6:
			lib.DeleteBook();
			break;
		case 0:
			cout << "退出成功" << endl;
			break;
		default:
			cout << "输入错误，请重新输入" << endl;
			break;
		}
	} while (input);
}

void reader(Library& lib)
{
	int input = 0;
	do
	{
		MenuOfReader();
		printf("请输入你的选择:>");
		cin >> input;
		switch (input)
		{
		case 1:
			lib.DisplayAllBook();
			break;
		case 2:
			lib.DisplayBook();
			break;
		case 3:
			lib.LoanBook();
			break;
		case 4:
			lib.ReturnBook();
			break;
		case 5:
			lib.Register();
			break;
		case 6:
			lib.Logout();
			break;
		case 0:
			cout << "退出成功" << endl;
			break;
		default:
			cout << "输入错误，请重新输入" << endl;
			break;
		}
	} while (input);
}

void test()
{
	Library lib;
//    Library lib2 = lib;
//    lib2 = lib;
	int input = 0;
	do
	{
		menu();
		printf("请输入你的选择:>");
		cin >> input;
		switch (input)
		{
		case 1:
			manager(lib);
			break;
		case 2:
			reader(lib);
			break;
		case 0:
			cout << "退出成功" << endl;
			break;
		default:
			cout << "输入错误，请重新输入" << endl;
			break;
		}
	} while (input);
}

int main()
{
	test();
	return 0;
}

有点丑陋了，全是switch case语句。

综上，就是STL的容器练习，以及类和对象的使用。