library

#include<iostream>
#include <string.h>
#include <fstream>
#include <cstring>
#include <string>
#include <conio.h>
#include <stdlib.h>
#include <iomanip>
using namespace std;

class item
{
    private:
        int code;
        char name[15];
        int Qty;
    public:
        void get_item(void);
        void put_item(void);
        int get_code(void);
void update_Qty(int num)
  {
    Qty=Qty-num;
  }
};


void item :: get_item(void)
{
    cout<<"Vyvedi nomera na kniga:"; cin>>code;
    fflush(stdin);
    cout<<"Vyvedi zaglavie na kniga:"; cin>>name;
    cout<<"Vyvedi broi knigi:"; cin>>Qty;
}

void item:: put_item(void)
  {
    cout<<setw(6)<<code
    <<setw(15)<<name
    <<setw(6)<<Qty<<endl;
  }


void add_record(void);
void show_record(void);
void show_All(void);
void delete_record(void);
void modify_record(void);

item it;
fstream file;


int main()
{
    int option;
    while(1)
    { system("cls");
      cout<<"***Menu***"<<endl;
      cout<<"1.Dobavi nov zapis"<<endl;
      cout<<"2.Pokaji vsichki zapisi"<<endl;
      cout<<"3.Pokaji izbran zapis"<<endl;
      cout<<"4.Iztrii zapis"<<endl;
      cout<<"5.Redaktirai zapis"<<endl;
      cout<<"6.Izhod"<<endl;
      cout<<"Izberi opciq No.: "; cin>>option;
      switch(option)
      {
       case 1:{ add_record();
                cout<<"Natisni buton za vryshtane v glavnoto menu...";
                getch();
                break;
            }
     case 2:{
                    cout<<"--------------------------------------------\n";
                    cout<<setw(6)<<"Code"<<setw(15)<<"Name"<<setw(6)<<"Qty"<<endl;
                    cout<<"--------------------------------------------\n";
                    show_All();
                    cout<<"--------------------------------------------\n";
                    cout<<"Natisni buton za vryshtane v glavnoto menu...";
                    getch();
                    break;
            }
    case 3:{
                show_record();
                cout<<"Natisni buton za vryshtane v glavnoto menu...";
                getch();
                break;
            }
    case 4:{
                delete_record();
                cout<<"Natisni buton za vryshtane v glavnoto menu...";
                getch();
                break;
            }
    case 5:{    modify_record();
                cout<<"Natisni buton za vryshtane v glavnoto menu...";
                getch();
                break;
            }
    case 6:{
                exit(0);
            }
    default:{
                cout<<"Nevalidna komanda, Natisni buton za vryshtane v glavnoto menu...";
                getch();
                break;
            }
        }
    }
return 0;
}

void add_record()
{
    char ch= 'y';
    file.open("stock.bin", ios::app | ios::binary);
    while(ch=='y'|| ch=='Y')
    {
it.get_item();
file.write((char*)&it, sizeof(it));
cout<<"Dobavi oshte zapisi....(y/n)?";
cin>>ch;
    }
    file.close();
}

void show_All(void)
{
    file.open("stock.bin", ios::in | ios::binary);
    if(! file)
    {
        cout<<"Faila ne e nameren";
        exit(0);
    }
else
{
    file.read((char*)&it, sizeof(it));
    while(! file.eof())
    {
        it.put_item();
        file.read((char*)&it, sizeof(it));
    }

}
file.close();
}

void show_record(void)
{
    int no, flag = 0;
    file.open("stock.bin", ios::in| ios::binary);
    if(!file)
    {
        cout<<"Faila ne e nameren";
        exit(0);
    }
else
{
    cout<<"Vyvedete nomera na kniga: ";
    cin>>no;
    file.read((char*)&it, sizeof(it));
    while(!file.eof())
    {
        if(no==it.get_code())
        {
            flag=1;
            cout<<"--------------------------------------------\n";
            cout<<setw(6)<<"Code"<<setw(15)<<"Name"<<setw(6)<<"Qty"<<endl;
            cout<<"--------------------------------------------\n";
            it.put_item();
            cout<<"--------------------------------------------\n";
            break;
        }
        file.read((char*)&it, sizeof(it));
    }
    if(flag==0)
    {
        cout<<"Produkta ne e nameren...\n";
    }
}
file.close();
}

void delete_record()
{
    int no;
    cout<<"Vyvedete nomer na kniga za iztrivane: ";
    cin >> no;
    ofstream file2;
    file2.open("new.bin", ios::out|ios::binary);
    file.open("stock.bin", ios:: in|ios::binary);
    if(! file)
    {
        cout<<"Faila ne e nameren";
        exit(0);
    }
else
{
    file.read((char*)&it, sizeof(it));
    while(!file.eof())
    {
        if(no!= it.get_code())
        {
            file2.write((char*)&it, sizeof(it));
        }
        file.read((char*)&it, sizeof(it));

    }
}
file2.close();
file.close();
remove("stock.bin");
rename("new.bin", "stock.bin");
}

void modify_record(void)
{
    int no, num;
    cout<<"Vyvedete nomer na kniga za redakciq:"; cin >> no;
    cout<<"Vyvedete kolichestvo: "; cin >> num;
    file.open("stock.bin", ios:: in| ios::out | ios::binary);
    if(! file)
    {
        cout<<"Faila ne e nameren";
        exit(0);

    }
    while (file.read((char*)&it, sizeof(it)))
    {
        if(it.get_code()== no)
        {
            it.update_Qty(num);
            int pos = sizeof(it);
            file.seekp(-pos, ios::cur);
            file.write((char*)&it, sizeof(it));
        }
    }
    file.close();
}