bdatebase.h

这是图书管理系统的Ｃ＋＋源代码．能够完成借书

#include<iostream.h>
#include"Book.h"
#include <string.h>
#include <fstream.h>//输入/输出文件流类
//图书库类，实现对图书的维护，查找，删除等
class BDatabase
{
  private:
    int top;         //图书记录指针
	Book book[Maxb]; //图书记录
  public:
	BDatabase()//构造函数，将book.txt读到book[]中
	{ /*
			Book b;
			top=-1;
			fstream file("book.txt",ios::in);
			while (1)
			{
				file.read((char *)&b,sizeof(b));
				if (!file) break;
				top++;
				book[top]=b;
			}
			file.close();
			*/
	}
    void clear()//全删
	{
		top=-1;
	}
    int addbook(int n,char *na)//增加图书
	{
		Book *p=query(n);
		if (NULL==p)
		{
			top++;
			book[top].addbook(n,na);
			return 1;
		}
		return 0;
	}
	Book *query(int bookid)//查找图书
	{
		for (int i=0;i<=top;i++)
			if (book[i].getno()==bookid &&book[i].gettag()==0)
			{	
				return &book[i];
			}
			return NULL;
	}
	void bookdata();//图书库维护
	void disp()
	{
	  for (int i=0;i<=top;i++)
		  if (book[i].gettag()==0)
			  book[i].disp();
	}
	~BDatabase()//析构函数，将book[]写到book.txt文件中
	{
		fstream file("book.txt",ios::out);
        for (int i=0;i<=top;i++)
			if (book[i].gettag()==0)
				file.write((char *)&book[i],sizeof(book[i]));
			file.close();
	}
};
void BDatabase::bookdata()
{
    char choice;
	char bname[40];
	int bookid;
	Book *b;
	while (choice!='0')
	{
		cout <<"\n\n\n\t\t\t图  书  维  护 "<<endl<<endl;
		cout<<"\t\t1   新     增\n \t\t2   更     改\n\t\t3   删     除\n\t\t4   查     找\n\t\t5   显     示\n\t\t6   全     删\n\t\t0   退     出"<<endl;
		cin >> choice;
		switch (choice)
		{
            case '1':
				cout << "输入图书编号:"<<endl;
				cin >> bookid;
                cout << "输入图书书名:"<<endl;
				cin >> bname;
				addbook(bookid,bname);
				break;
            case '2':
				cout << "输入图书编号:"<<endl;
				cin >> bookid;
				b=query(bookid);
				if (b==NULL)
				{
					cout << " 该图书不存在  "<<endl;
				    break;
				}
				cout << "输入新的书名:"<<endl;
				cin >> bname;
				b->setname(bname);
			 	break;
            case '3':
				   	cout <<" 读入图书编号:"<<endl;
                    cin >> bookid;
					b=query(bookid);
					if (b==NULL)
					{
					    cout <<" 该图书不存在" << endl;
					    break;
					}
					b->delbook();
					break;
			case '4':
				cout << "  读入图书编号:"<<endl;
				cin >> bookid;
				b=query(bookid);
				if (b==NULL)
				{
					cout <<"  该图书不存在"<< endl;
					break;
				}
				b->disp();
				break;
			case '5':
				disp();
				break;
			case '6':
				clear();
				break;
			default:cout<<"输入错误，请从新输入:";
		}
	}
}