The document describes a C++ program to copy records from one binary file to another based on area code. It defines a phonelist class with name, address, area code, and phone number fields. The TRANSFER() function opens the PHONE.DAT and PHONBACK.DAT files, reads each record from PHONE.DAT, and if the area code is "DEL" it writes the record to PHONBACK.DAT. The main function gets user input to populate PHONE.DAT, then calls TRANSFER() to copy records to PHONBACK.DAT, and finally displays the copied records.

1. /*Q.12 Given a binary file PHONE.DAT, containing records of the following structure type-:
class phonlist
{
char Name[20] ;
char Address[30] ;
char AreaCode[5] ;
char phoneNo[15] ;
public :
void Register();
void show();
};
Write a function TRANSFER() in C++, that would copy all those records which are having
AreaCode as "DEL" from PHONE.DAT to PHONBACK.DAT. */
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
#include<fstream.h>
#include<string.h>
class phonelist
{
char name[20] ;
char address[30] ;
char areacode[5] ;
char phoneno[15] ;
public :
void reg()
{
cout<<"enter name : ";
gets(name);
cout<<"enter address : ";
gets(address);
cout<<"enter areacode : ";
gets(areacode);
cout<<"enter phone number : ";
gets(phoneno);
}
void show()
{

2. cout<<"enter name : ";
cout<<"enter address : ";
cout<<"enter areacode : ";
cout<<"enter phone number : ";
}
char* return_code()
{
return areacode;
}
}p[5] ;
void main()
{
phonelist temp;
int n,i;
cout<<"for how many people you wish to enter the details ";
cin>>n;
ofstream fout;
fout.open("phone.dat",ios::binary);
//writing in phone.dat
for(i=0;i<n;i++)
{
p[i].reg();
fout.write((char*)&p[i],sizeof(phonelist));
}
ifstream fin;
fin.open("phone.dat",ios::binary);
fin.open("phone.dat",ios::binary);
fout.open("phoneback.dat",ios::binary);
//transferring records with del areacode to phoneback.dat

3. i=0;
while(fin)
{
fin.read((char*)&temp,sizeof(phonelist));
if(strcmp("del",p[i].return_code())==0)
{
fout.write((char*)&temp,sizeof(phonelist));
i++;
}
}
//displaying the records in phoneback.dat
fin.open("phoneback.dat",ios::binary);
while(fin)
{
fin.read((char*)&temp,sizeof(phonelist));
temp.show();
}
fin.close();
fout.close();
getch();
}
/*Q.11 Write a program in C++ to transfer a particular type of stock from the file "stock.dat" to
another file "Site.dat". Assuming that the binary file is containing the records of following
structure:
struct Products
{
int id;
char Iname[30];
int type;
};
Remember that transfer means deletion from the "stock.dat" file and addition in the "site.dat"
file.

4. */
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
#include<fstream.h>
struct products
{
int id;
char iname[30];
int type;
};
void main()
{
products p[5],temp;
int n,t,i;
cout<<"for how many products you wish to enter information ";
cin>>n;
ofstream fout;
fout.open("stock.dat",ios::binary);
//entering the details in stock file
for(i=0;i<n;i++)
{
cout<<"enter id : ";
cin>>p[i].id;
cout<<"enter name : ";
gets(p[i].iname);

5. cout<<"enter type : ";
cin>>p[i].type;
fout.write((char*)&p[i],sizeof(products));
}
fout.close();
cout<<"which type of stock you wish to transfer to other file ";
cin>>t;
ifstream fin;
fin.open("stock.dat",ios::binary);
fout.open("site.dat",ios::binary);
i=0;
//loop to transfer the specified records in site file
while(fin)
{
fin.read((char*)&temp,sizeof(products));
if(p[i].type==t)
fout.write((char*)&temp,sizeof(products));
i++;
}
fin.close();
fout.close();
remove("stock.dat");
fin.open("site.dat",ios::binary);

6. while(fin)
{
fin.read((char*)&temp,sizeof(products));
cout<<" id : "<<temp.id;
cout<<"n name : "<<temp.iname;
cout<<"n type : "<<temp.type;
}
fin.close();
getch();
}