~cpp 
#include <iostream> 
#include <fstream> 
#include <cmath> 
#include <string> 
using namespace std; 
 
#include <vector> 
 
 
class UserInfo 
{ 
private: 
        string szName;				// User's name
        unsigned int nSchoolNumber;			// User's school number
 
public: 
        UserInfo() {} 
        UserInfo( string szN, unsigned int nSN ) 
        { 
                szName = szN; 
                nSchoolNumber = nSN; 
        } 
        unsigned int getSchoolNumber() { return nSchoolNumber; } 
        string getName() { return szName; } 
}; 
 
class BookInfo 
{ 
private: 
        int nBookNumber; 
        string szBookName; 
        string szWriter; 
        string szPublishingCompany; 
 
        bool bLone; 
        UserInfo * pLendPeople; 
         
public: 
        BookInfo() {} 
        BookInfo( int nBN, string szBName, string szW, string szPC ) 
        { 
                nBookNumber = nBN; 
                szBookName = szBName; 
                szWriter = szW; 
                szPublishingCompany = szPC; 
 
                bLone = false; 
        } 
 
        int getBookNumber() { return nBookNumber; } 
        string getBookName() { return szBookName; } 
        string getWriter() { return szWriter; } 
        string getPublishingCompany() { return szPublishingCompany; } 
 
        void lendBook(UserInfo * pUi) { pLendPeople = pUi; bLone = true; } 
         
}; 
 
class DataBase 
{ 
private: 
        int nNextBookNumber; 
        vector <UserInfo *> userinfo; 
        vector <BookInfo *> bookinfo; 
 
public: 
        DataBase() 
        { 
			// Read the number of Book...
                ifstream f; 
                f.open("BookNumber.dat"); 
 
                string szNextNum;
                while (!f.eof())
                        getline(f, szNextNum);
 
                unsigned int nTNN; 
                double nTNN2; 
                for (int k = 0 ; k < szNextNum.size() ; k++)		// convert 'char' into 'int'
                {
                        nTNN += ( szNextNum[k] - 48 ) * pow(10.0, nTNN2); 
                        nTNN2--; 
                } 
 
                nNextBookNumber = nTNN;
				f.close();

			// end

			// Read data from UserData file...
 
                ifstream fin; 
                fin.open("UserData.dat"); 
 
                string szTemp; 
                vector <int> nT; 
 
                unsigned int nTempNum = 0; 
                double nTempNum2 = 0.0; 
 
                 
                while (!fin.eof()) 
                { 
                        getline(fin, szTemp); 
                        for (int i = 0 ; i < szTemp.size() ; i++) 
                        { 
                                if ( szTemp[i] == ',' ) 
                                        nT.push_back(i); 
                        } 
 
                        string szTempNum(szTemp.begin(), szTemp.begin() + nT[0]); 
                        string szTempName(szTemp.begin() + nT[0] + 1, szTemp.size()); 
 
                        nTempNum2 = szTempNum.size() - 1; 
 
                        for (int j = 0 ; j < szTempNum.size() ; j++)		// convert 'char' into 'int'
                        { 
                                nTempNum += ( szTempNum[j] - 48 ) * pow(10.0, nTempNum2); 
                                nTempNum2--; 
                        } 
 
                        UserInfo * ui = new UserInfo(szTempName , nTempNum); 
 
                        userinfo.push_back(ui); 
                } 
 
                fin.close();

			// end


			// Read data from BookData file... 
 
                ifstream fin2; 
                fin2.open("BookData.dat"); 
 
                string szTemp2; 
                vector <int> nT2; 
 
                nTempNum = 0; 
                nTempNum2 = 0.0; 
 
 
                while (!fin2.eof()) 
                { 
                        getline(fin2, szTemp2); 
                        for (int i = 0 ; i < szTemp2.size() ; i++) 
                        { 
                                if ( szTemp2[i] == ',' ) 
                                        nT2.push_back(i); 
                        }

						// string 변수(배열 시작, 배열 마지막);
 
                        string szTemp2BookNum(szTemp2.begin(),                          szTemp2.begin() + nT2[0]); 
                        string szTemp2BookName(szTemp2.begin() + nT2[0] + 1,            szTemp2.begin() + nT2[1]); 
                        string szTemp2Writer(szTemp2.begin() + nT2[1] + 1,              szTemp2.begin() + nT2[2]); 
                        string szTemp2PublishingCompany(szTemp2.begin() + nT2[2] + 1,   szTemp2.size()); 
 
                        nTempNum2 = szTemp2BookNum.size() - 1; 
 
                        for (int j = 0 ; j < szTemp2BookNum.size() ; j++)		// convert 'char' into 'int'
                        { 
                                nTempNum += ( szTemp2BookNum[j] - 48 ) * pow(10.0, nTempNum2); 
                                nTempNum2--; 
                        } 
 
                        BookInfo * bi = new BookInfo(nTempNum , szTemp2BookName , szTemp2Writer , szTemp2PublishingCompany); 
 
                        bookinfo.push_back(bi); 
                } 
 
                fin2.close();

			// end
 
 
        } 
 
        void insertUserData(UserInfo * ui) 
        { 
                userinfo.push_back(ui); 
        } 
 
        void deleteUserData(int nUserNum) 
        { 
                for (int i = 0 ; i < userinfo.size() ; i++) 
                { 
                        if ( userinfo[i]->getSchoolNumber() == nUserNum ) 
                        { 
                                userinfo.erase(userinfo.begin()+i); 
                                return; 
                        } 
                } 
        } 
 
        void insertBookData(BookInfo * bi) 
        { 
                bookinfo.push_back(bi); 
        } 
 
        void deleteBookData(int nBookNum) 
        { 
                for (int i = 0 ; i < bookinfo.size() ; i++) 
                { 
                        if ( bookinfo[i]->getBookNumber() == nBookNum ) 
                        { 
                                bookinfo.erase(bookinfo.begin()+i); 
                                return; 
                        } 
                } 
        } 
 
        int getNextBookNumber() { nNextBookNumber++; return nNextBookNumber; } 
 
        void showAll() 
        { 
 
        } 
};