UNIT 14: FILE HANDLING IN C++
Key unit competency
Open, close, create a data file in C++ and read, write and append data to Files
Introductory Activity
Observe the figure below and answer the following questions.
1. What do you understand by file?
2. Provide two examples of files.
3. How do we store files?
4. What do you understand by file size?
5. Create “BOOK.txt” file.
6. Put some text in the file created above
7. Write a function in C++ to count the number of uppercase alphabets
present in a text file “BOOK.txt”.
8. Write a function in C++ to count letters present in a text file “BOOK.txt”.
9. Write a function in C++ to count digits present in a text file “BOOK.txt”.
10. Write a function in C++ to count white spaces present in a text file
“BOOK.txt”
11. Write a function in C++ to count vowels present in a text file “BOOK.txt”.
14.1. Understanding files
Learning Activity 14.1.
1. Explain the types of files
2. Provide one example of each file type
3. Discuss the role of file name
4. Differenciate text file from binary files
Every program or sub-program consists of two major components: algorithm and
data structures.
The algorithm takes care of the rules and procedures required for solving the
problem and the data structures contain the data. The data is manipulated by the
procedures for achieving the goals of the program.
A data structure is volatile by nature in the sense that its contents are lost as soon
as the execution of the program is over. Similarly, an object also loses its states after
the program is over. To store permanently the data or to create persistent objects t
becomes necessary to store the same in a special data structure called file. The file
can be stored on a second storage media such as hard disk. In fact, vary large data is
always stored in a file.
14.1.1. File
A file is a self-contained piece of information available to the operating system and
any number of individual programs. A computer file can be thought of much like a
traditional file that one would find in an office’s file cabinet. Just like an office file,
information in a computer file could consist of basically anything.
Whatever program uses an individual file is responsible for understanding its
contents. Similar types of files are said to be of a common “format.” In most cases,
the easiest way to determine a file’s format is to look at the file’s extension.
Each individual file in Windows will also have a file attribute which sets a condition
to the specific file. For example, you can’t write new information to a file that has
the read-only attribute turned on.
A file name is just the name that a user or program gives the file to help identify what
it is. An image file may be named something (example of file name with extension:
kids-lake-2017.jpg). The name itself doesn’t affect the contents of the file, so even
if a video file is named something like image.mp4, it doesn’t mean it’s suddenly a
picture file.
Files in any operating system are stored on hard drives, optical drives, and other
storage devices. The specific way a file is stored and organized is referred to as a file
system.
Examples of Files:
An image copied from a camera to a computer may be in the JPG or TIF format.
These are files in the same way that videos in the MP4 format, or MP3 audio files, are
files. The same holds true for DOC/DOCX files used with Microsoft Word, TXT files
that hold plain text information, etc.
Though files are contained in folders for organization (like the photos in your Pictures
folder or music files in your iTunes folder), some files are in compressed folders, but
they’re still considered files. For example, a ZIP file is basically a folder that holds
other files and folders but it actually acts as a single file.
Another popular file type similar to ZIP is an ISO file, which is a representation of a
physical disc. It’s just a single file but it holds all the information found on a disc, like
a video game or movie.
From these few examples, it is clear that not all files are alike, but they all share a
similar purpose of holding information together in one place.
14.1.2. Types of files:
a. A. Binary Files
Binary files typically contain a sequence of bytes, or ordered groupings of eight bits.
When creating a custom file format for a program, a developer arranges these bytes
into a format that stores the necessary information for the application. Binary file
formats may include multiple types of data in the same file, such as image, video,
and audio data. This data can be interpreted by supporting programs, but will show
up as garbled text in a text editor. Below is an example of a .PNG image file opened
in an image viewer and a text editor.
As it is seen, the image viewer recognizes the binary data and displays the
picture. When the image is opened in a text editor, the binary data is converted
to unrecognizable text. However, some of the text is readable. This is because the
PNG format includes small sections for storing textual data. The text editor, while
not designed to read this file format, still displays this text when the file is opened.
Many other binary file types include sections of readable text as well. Therefore, it
may be possible to find out some information about an unknown binary file type by
opening it in a text editor.
Binary files often contain headers, which are bytes of data at the beginning of a
file that identifies the file’s contents. Headers often include the file type and other
descriptive information. For example, in the image above, the “PNG” text indicates
the file is a PNG image. If a file has invalid header information, software programs
may not open the file or they may report that the file is corrupted.
b. Text Files
Text files are more restrictive than binary files since they can only contain textual
data. However, unlike binary files, they are less likely to become corrupted. While
a small error in a binary file may make it unreadable, a small error in a text file may
simply show up once the file has been opened. This is one of reasons Microsoft
switched to a compressed text-based XML format for the Office 2007 file types.
Text files may be saved in either a plain text (.TXT) format or rich text (.RTF) format. A
typical plain text file contains several lines of text that are each followed by an Endof-
Line (EOL) character. An End-of-File (EOF) marker is placed after the final character,
which signals the end of the file. Rich text files use a similar file structure, but may also
include text styles, such as bold and italics, as well as page formatting information.
Both plain text and rich text files include a (character encoding| character encoding)
scheme that determines how the characters are interpreted and what characters
can be displayed.
Since text files use a simple, standard format, many programs are capable of reading
and editing text files. Common text editors include Microsoft Notepad and WordPad,
which are bundled with Windows, and Apple TextEdit, which is included with Mac
OS X.
c. The difference between binary and text files
All files can be categorized into one of two file formats: binary or text. The two
file types may look the same on the surface, but they encode data differently. While
both binary and text files contain data stored as a series of bits (binary values of
1s and 0s), the bits in text files represent characters, while the bits in binary files
represent custom data.
While text files contain only textual data, binary files may contain both textual and
custom binary data.
Application Activity 14.1.
1. Discuss text files and provide two examples.
2. Describe binary files and provide two examples.
3. Explain the role of file extension
4. Where are files stored?
14.2. File Streams
14.2.1. Introduction
One of the great strengths of C++ is its I/O system, IO Streams. As Bjarne Stroustrup
says in his book “The C++ Programming Language”, “Designing and implementing
a general input/output facility for a programming language is notoriously difficult”.
He did an excellent job, and the C++ IOstreams library is part of the reason for C++’s
success. IO streams provide an incredibly flexible yet simple way to design the input/
output routines of any application.
IOstreams can be used for a wide variety of data manipulations to the following
features:
A ‘stream’ is internally nothing but a series of characters. The characters may be either
normal characters (char) or wide characters (wchar_t). Streams provide users with a
universal character-based interface to any type of storage medium (for example,
a file), without requiring the to know the details of how to write to the storage
medium. Any object that can be written to one type of stream, can be written to all
types of streams. In other words, as long as an object has a stream representation,
any storage medium can accept objects with that stream representation.
Streams work with built-in data types, and the user can make user-defined types
work with streams by overloading the insertion operator (<<) to put objects into
streams, and the extraction operator (>>) to read objects from streams.
The stream library’s unified approach makes it very friendly to use. Using a consistent
interface for outputting to the screen and sending files over a network makes life
easier. The programs below will show what is possible.
14.2.2. Meaning of input and output
The input is whatever the user enters through a keyboard or any other input devices
while output what is written (displayed) on a output device being screen, printer
or file. The information input or output is considered as a stream of characters.
Suppose that the user enters the number 7479. The set of 4 characters: ‘7’, ‘4’, ‘7’ and
‘9’ taken as input can be considered as numbers or a string. the input characters
must be put into a recognizable data type for them to be of any use other than as a
character array.
IO streams not only define the relation between a stream of characters and the
standard data types but also allows the user to define a relationship between a
stream of characters and its classes. It also allows the user nearly limitless freedom
to manipulate those streams both using object oriented interfaces and working
directly on character buffers when necessary
14.2.3. Working with streams
Streams are serial interfaces to storage, buffers files, or any other storage medium.
The difference between storage media is intentionally hidden by the interface;
the usermay not even know what kind of storage he/she is working with but the
interface is exactly the same.
The “serial” nature of streams is a very important element of their interface. The
usercannot directly make random access: random reads or writes in a stream (unlike,
say, using an array index to access any wanted value) although he/she can seek to a
position in a stream and perform a read at that point.
Using a serial representation gives a consistent interface for all devices. Many devices
have the capability of both producing and consuming data at the same time; if data
is being continually produced, the simplest way to think about reading that data is
by doing a fetch of the next characters in a stream. If that data hasn’t been produced
yet (the user hasn’t typed anything, or the network is still busy processing a packet),
he/she waits for more data to become available, and the read will return that data.
Even if he/she tries to seek past the end (or beginning) of a stream, the stream
pointer (i.e. get or put pointer) will remain at the boundary, making the situation
safe. (Compare this with accessing data off the end of an array, where the behavior
is undefined.)
The underlying low-level interface that corresponds to the actual medium very
closely is a character buffer (the stream buffer, technically called the streambuf),
which can be thought of as the backbone of the stream. Being a buffer, it does not
hold the entire content of the stream, if the stream is large enough, so you can’t use
it for random access.
14.2.4. The most important of the basic stream operations are
First, the stream is initialized with the appropriate type (like a std::string for a
stringstream and the filename for an fstream) of values and suitable modes (like
ios::in for input and ios::out for output and many more depending on the type of the
stream).
After that, the user can specify where the I/O should occur, through the get and put
pointers. Depending on how the stream is opened, the location may already be set
appropriately (for example, if a file is opened with ios::app, the get pointer sets at the
end of the stream, allowing appends).
14.2.5. Functions of file stream classes
14.2.5.1. Introduction
In this brief introduction, the basic operations on both text and binary files are
discussed so that the functions to carry out these tasks are well understood.
The Basic File Operations on Text Files are:
• Creating an empty file – First time when a file is created with some valid
filename it is empty therefore it contains only EOF marker and a location
pointer pointing to it.
• Opening a file – A file is opened for reading/writing or manipulation of
data on it. If a file exists then only it can be opened , when a file is opened
the location pointer points to the Beginning of file.
• Closing a file – After the file operations done , the file should be closed. If
we don’t close the file it gets automatically closed when the program using
it comes to an end.
• Writing text into file – Once a file is created , data elements can be stored
to it permanently. The already existing contents are deleted if we try to
write data to it next time, rather we can append data to it and keep the
existing data.
• Reading of text from an already existing text file (accessing sequentially)
• Manipulation of text file from an already existing file – An existing file
is opened first and then the manipulation is done in sequential order. for
example – counting of words.
• Detecting EOF – When the data from the file is read in sequential order, the
location pointer will reach to the end of file. After reaching at the EOF no
attempt should be made to read data from the file.
• Copying of one text file to other text file
The Binary file operations are:
1. Creation of file – A binary file is always opened in binary mode for both
reading or writing. Upon successful creation, the pointer is set to the
beginning of the file.
2. Writing data into file – A binary file is opened in output mode for writing
data in it. A binary file contains non readable characters and write
function is used to write the records into file.
3. Searching for required data from file – a binary file is opened in input
mode for searching data. The file can be read sequentially one by one each
record or randomly by going to that particular location.
4. Appending data to a file – appending means addition of new records to
an already existing file.
5. Insertion of data in sorted file
6. Deletion of data
7. Modification/Updation of data
14.2.6. Components of c++ to be used with file handling
In C++ file input/output facilities are performed by a header file fstream.h, which
exists in the C++ standard library. C++ provides specific classes for dealing with user
defined streams. Every file in C++ is linked to a stream. A stream must be obtained
before opening a file. The file fstream.h is inherited from iostream.h, thus includes
all the classes included in iostream.h .
User defined streams – The four classes for file Input/Output are :
a. Ifstream – derived from istream and used for file input(reading). It inherits
the functions get(), getline() and read() and functions supporting random
access(seekg() and tellg() and >> operator. It also contains open(),close()
and eof().
b. ofstream – derived from ostream and used for file output(writing). It
inherits the functions put() and write() functions along with functions
supporting random access (seekp() and tellp() from ostream class. It also
contains open(),close() and eof().
c. fstream – derived form iostream and used for both input and output.
It inherits all the functions from istream and ostream classes through
iostream.h.
d. Filebuf – it sets the buffers to read and write and contains close() and
open() member functions in it.
14.2.7. Text File Operations
14.2.7.1. Reading Operation
a. Reading a File Character by character (including space,’\n’,’\t’)
Example:
Observe the following C++ program, interpret it and thereafter run it.
#include <iostream>
#include <fstream>
#include <string>
usingnamespace std;
int main () {
string line;
ifstream myfile (“example.txt”);
if (myfile.is_open())
{
while ( getline (myfile,line) )
{
cout << line <<’\n’;
}
myfile.close();
}
else cout <<”Unable to open file”;
return 0;
}
Explanations on how to write a program that reads from a file.
14.2.7.2. Writing in Text File
Example:
Observe the following C++ program, interpret it and thereafter run it:
#include <iostream>
#include <fstream>
usingnamespace std;
int main () {
ofstream myfile;
myfile.open (“example.txt”);
myfile <<”Writing this to a file.\n”;
myfile.close();
return 0;
}
Example:
Observe the following C++ program, interpret it and thereafter run it:
#include <iostream>
#include <fstream>
usingnamespace std;
int main () {
ofstream myfile (“example.txt”);
if (myfile.is_open())
{
myfile <<”This is a line.\n”;
myfile <<”This is another line.\n”;
myfile.close();
}
else cout <<”Unable to open file”;
return 0;
}
Binary Files are also called fixed length files or packed files as all the fields in a binary
file occupy fixed number of bytes.
For Opening files C++ provides mechanism for opening file in different modes:
Note:
A file can be opened in more than one modes by making use of pipe sign as follows:
fstream file(“ABC”,ios::in|ios::binary|ios::out);
a. Writing class object to binary File (assuming student class ) and
function is a member function
b. Writing Structure object to binary File (assuming student is structure,
containing name and avg as members)
14.2.7.4. Reading a Binary File
Example:
Observe the following program, interpret it and run it:
#include <iostream>
#include <fstream>
usingnamespace std;
int main () {
streampos size;
char * memblock;
ifstream file (“example.bin”, ios::in|ios::binary|ios::ate);
if (file.is_open())
{
size = file.tellg();
memblock = newchar [size];
file.seekg (0, ios::beg);
file.read (memblock, size);
file.close();
cout <<”the entire file content is in memory”;
delete[] memblock;
}
else cout <<”Unable to open file”;
return 0;
}
a. Sequential reading
Sequential reading means reading record one by one until end of file and all the
records are displayed.
Displaying selected records -This is condition based display, where the condition
is checked after reading. If the reading is concerned with reading class objects then
there will be a function in class as a public member which will return that particular
value that is to be evaluated. If the structure instance is to be read from file then
the normal comparison can be done after executing the file read statement. If the
condition is true then call display function or display the record.
Display Records from file where average marks are greater than 60
b. Random Access
Up till now we had been writing and reading the files in sequential manner but
binary files, being fixed length files, provides liberty to perform read and write
operations randomly. C++ provides functions for it. When you open a file operating
system assigns two exclusive pointers to file object. In C++ these pointers are called
get pointer(input) and put pointer(output) . These pointers provide you the facility
to move to the desired place in the file to perform read, write operations. The get
pointer specifies a location from where the current reading operation is initiated.
The put pointer specifies a location where the current write operation will take place.
14.2.7.5. Functions for manipulating file pointers
a. Random record reading
File pointer position is set according to the record number to be displayed. The file
pointer directly can be set to the position using seekg().
Note:- when file is opened in input or output mode the file pointer is at the starting
i.e. at 0 position. In append mode the file pointer is at the end of file, and the writing
continues by adding the records.
void readrec()
{
ifstreamfin(“stud.dat”,ios::binary|ios::in);
stud s;
int rec;
cout<<”enter the record you want to display”;
cin>>rec;
fin.seekg((rec-1)*sizeof(stud),ios::beg); // by default ios::beg is default argument
fin.read((char*)&s,sizeof(stud));
s.display();
getch();
}
b. Updation of record in existing file
In this the record to be updated is asked from the user, then appropriate position of
file pointer is obtained and pointer is set and writes operation is performed.
Eg.– writing a program to update structure/class object to update.
c. Insertion in Sorted file
The record to be inserted in a sorted file is accepted as a separate object. The file
in which the record is to be inserted, is opened in input mode. The records with
record key smaller than the record key to be inserted are copied to temporary file
and then record to be inserted is copied, following with rest of the records if any.
After that original file is removed using remove() and temporary file is renamed with
the original name with rename().
d. Deletion of record from file
The logic of deleting record is:
1. Accept the record key for the record you want to delete.
2. Read the file sequentially , from which the record is to be deleted and
copied down the records to temporary file except the record you want to
delete (by comparing the record value)
3. Remove the original file and rename the temporary file with the original
file name.
Sorting the records of an existing file - First the records in the file are counted . an
array of objects is created dynamically / statically with the approx. index value as
compared to number of records.
And read the file using the following statement:
while (fin.read(char*)&obj[i++],sizeof(class))); After reading the file , sort the array
with any sorting technique(Bubble/Insertion/Selection) Then write the sorted array
in to the file opened in output mode.
Notes:-
1. Multiple File Handling-
In this case the point to remember is:
a)Identify the file mode to be opened .
b) One object can open only one file at a time.
2. Sizeof() operator gives the sizeof data type.
3. The data written to a file using write() can only be read accurately using
read().
4. The files are closed using destructor of file object, if not closed using
close(). It is must to close the file. If the file pointer is opening another file
in the same program otherwise it is a good practice to use close().
Learning Activity 14.2.
1. Write a C++ program to open and read text from a text file character
by character in C++. We have a file named “test.txt”, this file contains
following text:
Hello friends, how are you?
I hope you are fine and learning well.
Thanks.
We will read text from the file character by character and display it on the output
screen.
2. Using C++, create a file and then write some text into that file, after
writing text file it will be closed and again file will open in read mode,
read all written text.
3. Provide a C++ program to write and read variable’s values in/from text
file. Here you will show how to write values in file and how to access
them.
4. Give a C++ program to write and read values through object in/from
text files. Demonstrate how to write object value in file and how to
access them.
5. The function tellg() and tellp() are predefined functions which tells
(returns) the position of the get and put pointers. Write a C++ program
to demonstrate example of tellg() and tellp() function.
14.2.7.6. Closing a file
a. Detecting the End of a File
The eof() member function reports when the end of a file has been encountered.
if (inFile.eof())
inFile.close();
A File is closed by disconnecting it with the stream it is associated with. The close
function is used to accomplish this task.
Syntax:
Stream_object.close
;
Example :
fout.close();
eof
This function determines the end-of-file by returning true (non-zero) for end of file
otherwise returning false(zero).
Syntax
Stream_object.eof
Example :
fout.eof
b. Testing for Open Errors
dataFile.open(“cust.dat”, ios::in);
if (!dataFile)
{
cout << “Error opening file.\n”;
}
Another way to Test for Open Errors
dataFile.open(“cust.dat”, ios::in);
if (dataFile.fail())
{
cout << “Error opening file.\n”;
}
Note on eof():
In C++, “end of file” doesn’t mean the program is at the last piece of information
in the file, but beyond it. The eof() function returns true when there is no more
information to be read.
Application activity 14.3.:
1. Write a C++ program that demonstrates the declaration of an fstream
object and the opening of a file.
2. Write a C++ program that demonstrates the opening of a file at the time
the file stream object is declared.
3. Write a C++ program that demonstrates the close function.
4. Write C++ program that uses the << operator to write information to a
file. The Program Screen Output will display:
File opened successfully.
Now writing information to the file.
Done.
And the Output to file demofile.txt will be:
Jones
Smith
Willis
Davis
5. This program writes information to a file, closes the file, then reopens it
and appends more information.
6. Write a program to create a binary file ‘student.dat’ using structure.
7. Program to read a binary file ‘student.dat’ display records on monitor.
8. Write the program that writes the information to a file, closes the file,
then reopens it and appends more information.
9. Provide a C++ program that will demonstrate how to write and read
time in/from binary file using fstream. Remember that there will be two
functions: writeTime() - that will write time into the file and readTime() -
that will read time from the file. In the program, there are two things to
be noticed, how time will be formatted into a string (using sprintf ) and
how time values will be extracted from the string (using sscanf ).
10. Write a C++ program to read an employee’s details from keyboard
using class and object then write that object into the file. The program
will also read the object and display employee’s record on the screen.
This program is using following file stream (file handling) functions.
There will be the following functions:
•• file_stream_object.open() to open a file
•• file_stream_object.close() to close the file
•• file_stream_object.write() to write an object into the file
•• file_stream_object.read() to read object from the file
In this program there are following details to be read through Employee class
•• Employee ID
•• Employee Name
•• Designation
•• Date of joining
•• Date of birth
Observe the program segment carefully and answer the question that follows:
class stock
{
int Ino, Qty; Char Item[20];
public:
void Enter() { cin>>Ino; gets(Item); cin>>Qty;}
void issue(int Q) { Qty+=0;}
void Purchase(int Q) {Qty-=Q;}
int GetIno() { return Ino;}
};
void PurchaseItem(int Pino, int PQty)
{ fstream File;
File.open(“stock.dat”, ios::binary|ios::in|ios::out);
Stock s;
int success=0;
while(success= = 0 && File.read((char *)&s,sizeof(s)))
{
If(Pino= = ss.GetIno())
{
s.Purchase(PQty);
_______________________ // statement 1
_______________________ // statement 2
Success++;
}
}
if (success = =1)
cout<< “Purchase Updated”<<endl;
else
cout<< “Wrong Item No”<<endl;
File.close() ;
}
a. Statement 1 to position the file pointer to the appropriate place so that
the data updating is done for the required item.
b. Statement 2 to perform write operation so that the updating is done in
the binary file.
1. Write C++ program that uses the file stream object’s eof() member
function to detect the end of the file.
Summary:
Let us talk briefly about some key concepts of file streams discussed here above:
filebuf
It sets the buffer to read and write, it contains close() and open() member functions
on it.
fstreambase
This is the base class for fstream and, ifstream and ofstream classes. therefore it
provides the
common function to these classes. It also contains open() and close() functions.
ifstream
Being input class it provides input operations it inherits the functions get
), read
and random access functions seekg
ofstream
Being output class it provides output operations it inherits put
access
functions seekp
fstream
It is an I/O class stream, it provides simultaneous input and output operations.
File modes
Meaning of file mode:
The file mode describes how a file is to be used ; to read from it, write to it, to append
and so on
Syntax
Stream_object.open(“filename”,mode);
File Modes are briefly discussed here below:
ios::out: It open file in output mode (i.e write mode) and place the file pointer in
beginning, if
file already exist it will overwrite the file.
ios::in: It open file in input mode (read mode) and permit reading from the file.
ios::app: It open the file in write mode, and place file pointer at the end of file i.e to
add new
contents and retains previous contents. If file does not exist it will create a new file.
ios::ate: It open the file in write or read mode, and place file pointer at the end of
file i.e input/
output operations can performed anywhere in the file.
ios::trunc: It truncates the existing file (empties the file).
ios::nocreate: If file does not exist this file mode ensures that no file is created and
open() fails.
ios::noreplace If file does not exist, a new file gets created but if the file already
exists, the
open() fails.
ios::binary Opens a file in binary mode.
Logic to read a text file:
• 1. Open file in read/input mode using std::in
• 2. Check file exists or not, if it does not exist terminate the program
• 3. If file exist, run a loop until EOF (end of file) not found
• 4. Read a single character using cin in a temporary variable
• 5. And print it on the output screen
• 6. Close the file
End unit assessment
1. Write a function in C++ to search for details (Phoneno and Calls) of those
Phones which have more than 800 calls from binary file “phones.dat”.
Assuming that this binary file contains records/ objects of class Phone,
which is defined below.
class Phone
{
Char Phoneno[10]; int Calls;
public:
void Get() {gets(Phoneno); cin>>Calls;}
void Billing() { cout<<Phoneno<< “#”<<Calls<<endl;}
int GetCalls() {return Calls;}
};
2. Write a function in C++ to add new objects at the bottom of a binary file
“STUDENT.DAT”, assuming the binary file is containing the objects of the
following class:
class STUD
{
int Rno;
char Name[20];
public:
void Enter()
{cin>>Rno;gets(Name);}
void Display(){cout<<Rno<<Name<<endl;}
};
3. Given a binary file PHONE.DAT, containing records of the following class
type
class Phonlist
{
char name[20];
char address[30];
char areacode[5];
char Phoneno[15];
public:
void Register()
void Show();
void CheckCode(char AC[])
{return(strcmp(areacode,AC);
};
Write a function TRANSFER
having areacode as “DEL” from PHONE.DAT to PHONBACK.DAT.
4. Given a binary file SPORTS.DAT,containg records of the following structure
type:
struct Sports
{
char Event[20] ; char Participant[10][30] ;
} ;
Write a function in C++ that would read contents from the file SPORTS.DAT and
creates a file named ATHLETIC.DAT copying only those records from SPORTS.DAT
where the event name is “Athletics”.
5. 5.Given a binary file TELEPHON.DAT, containing records of the following
class Directory :
class Directory { char Name[20] ; char Address[30] ;
char AreaCode[5] ; char phone_No[15] ; public ;
void Register
int CheckCode(char AC[ ])
{ return strcmp(AreaCode, AC) ;
}
} ;
Write a function COPYABC
AreaCode as “123” from TELEPHON.DAT to
TELEBACK.DAT.
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