Basic file operations in C++ involve opening, reading from, and writing to files. The key classes for input/output with files are ofstream for writing, ifstream for reading, and fstream for both reading and writing. A file must first be opened before performing any operations on it. Common operations include writing data to files with put() or write(), reading data from files with get() or read(), and closing files after completion. Proper opening modes and error handling should be used to ensure successful file input/output.

1. Basic file operations in C++
Dr. Ahmed Telba
1

2. 2
Learning Objectives
C++ I/O streams.
Reading and writing sequential files.
Reading and writing random access files.

3. 3
Table 12-1
File Name and Extension File Contents
M Y P R O G .B A S BASIC program
M E N U .B A T DOS Batch File
I N S T A L L .D O C Documentation File
C R U N C H .E X E Executable File
B O B .H T M L HTML (Hypertext Markup Language)
File
3 D M O D E L .J A V A Java program or applet
I N V E N T .O B J Object File
P R O G 1 .P R J Borland C++ Project File
A N S I .S Y S System Device Driver
R E A D M E .T X T Text File

4. 4
Figure 1-1

5. 5
Figure 1-2

6. 6
4.1 What is a File?
A file is a collection on information, usually
stored on a computer’s disk. Information
can be saved to files and then later reused.

7. 7
4.2 File Names
All files are assigned a name that is used for
identification purposes by the operating
system and the user.

8. 8
Setting Up a Program for File Input / Output
Before file I/O can be performed, a C++
program must be set up properly.
File access requires the inclusion of
# include <fstream>

9. Input &Output with files
Input / Output with files
C++ provides the following classes to perform
output and input of characters to/from files:
ofstream: Stream class to write on files
ifstream: Stream class to read from files
fstream: Stream class to both read and write
from/to files.
9

10. 10
Path of file
Before data can be written to or read from a
file, the file must be opened.
ifstream inputFile;
inputFile.open(“customer.dat”);
// Path of file using :
ifstream fin("D:data.txt ");

11. 11
C++ Files and Streams
Why use File Handling
For permanent storage.
The transfer of input - data or output - data
from one computer to another can be easily
done by using files.
For read and write from a file you need
another standard C++ library called fstream,
which defines three new data types:

12. How to achieve File Handling
For achieving file handling in C++ we
need follow following steps
• Naming a file
• Opening a file
• Reading data from file
• Writing data into file
• Closing a file
12

13. Input &Output with files
Input / Output with files
C++ provides the following classes to perform
output and input of characters to/from files:
ofstream: Stream class to write on files
ifstream: Stream class to read from files
fstream: Stream class to both read and write
from/to files.
13

14. Functions use in File Handling
Function Operation
open() To create a file
close() To close an existing file
get() Read a single character from a file
put() write a single character in file.
read() Read data from file
write() Write data into file.
14

15. 15
Closing a File
A file must be close after completion of all operation related to
file. For closing file we need close() function.
Syntax
outfile.close();
Defining and Opening a File
The function open() can be used to open multiple files that use
the same stream object.
Syntax
file-stream-class stream-object;
stream-object.open("filename");
Example
ofstream outfile; // create stream
outfile . open ("data1"); // connect stream to data1

16. File Opening mode
Mode Meaning Purpose
ios :: out Write Open the file for write only.
ios :: in read Open the file for read only.
ios :: app Appending Open the file for appending data to end-of-file.
ios :: ate Appending take us to the end of the file when it is opened.
16
Example
fstream file;
file.Open("data . txt", ios :: out | ios :: in);

17. FLAGES IN FILE
FLAGES IN FILE
17

18. 18
File Open Modes
ios:: app - (append) write all output to the end of file
ios:: ate - data can be written anywhere in the file
ios:: binary - read/write data in binary format
ios:: in - (input) open a file for input
ios::out - (output) open afile for output
ios: trunc -(truncate) discard the files’ contents if
it exists

19. // basic file operations writing to file
#include <iostream>
#include <fstream>
using namespace std;
int main () {
ofstream myfile;
myfile.open ("example.txt");
myfile << "Writing this to a file.n";
cout<<" myfile " << "Writing this to a file.n";
myfile << "Writing this to a file.n";
cout<<" myfile " << "Writing this to a file.n";
myfile << "Writing this to a file.n";
cout<<" myfile " << "Writing this to a file.n";
myfile << "Writing this to a file.n";
myfile.close();
return 0;
}
19

20. Writing to file
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
char x = 's';
int d = 77;
double i = 3.14;
ofstream fout("data2.txt");
fout << x << d << ' ' << i ;
cout << x << d << ' ' << i ;
fout.close();
cout << "File Completedn";
return 0;
}
20

21. #include <iostream>
#include <fstream>
using namespace std;
int main()
{
ofstream fout;
fout.open("FF.txt");
fout << "HELLOW FILE .n"<< "WELCOME YOU PROGRAMn"
<< "WHAT DA YOU LIKE OF MEn";
fout.close();
}
21

22. // writing in file
#include<iostream> //divide by 7
#include <fstream>
using namespace std;
int main()
{
ofstream fout("data.txt");
for(int i=4;i<=200;i++)
{
if(i%7==0)
fout<<i<<" : divide by Two (7) ."<<"n";
}
fout.close();
}
22

23. #include<iostream>//prime number
#include<fstream>
using namespace std;
int main()
{
ofstream fout("prime2.txt");
int num;
bool prime;
cout << "Please enter a positive integer" << endl;
cin >> num;
for(int i = 3; i <= num; i++){
prime = true;
for(int n = 2; n <= i - 1; n++){
if(i % n == 0){
prime = false;
}
}
if(prime){
cout << i << " is prime" << endl;
fout << i << " is prime" << endl;
}
}
}
23

24. #include<iostream>// !x=x*(x-1)*(x-2)….
#include<fstream>
using namespace std;
int main()
{
ofstream fout("factial2.txt");
// Variable Declaration
int counter, n, fact = 1;
// Get Input Value
cout<<"Enter the Number :";
cin>>n;
//for Loop Block
for (int counter = 1; counter <= n; counter++)
{
fact = fact * counter;
}
fout<<n<<" Factorial Value Is "<<fact;
fout.close();
cout<<n<<" Factorial Value Is "<<fact;
return 0;
}
24

25. 25
Testing for Open Errors
dataFile.open(“cust.txt”, ios::in);
if (!dataFile)
{
cout << “Error opening file.n”;
}

26. 26
Another way to Test for Open
Errors
dataFile.open(“cust.dat”, ios::in);
if (dataFile.fail())
{
cout << “Error opening file.n”;
}

27. // writing on a text file
// writing on a text file
#include <iostream>
#include <fstream>
using namespace std;
int main () {
ofstream myfile ("examplett.dat");
if (myfile.is_open())
{
myfile << "This is a new file created in cpp.n";
myfile << "This is another line.n";
myfile.close();
}
else cout << "Unable to open file";
return 0;
}
27

28. file operations in C++
#include <fstream>
#include <iostream>
using namespace std;
int main ()
{ ofstream myfile;
myfile.open ("example22.txt");
myfile << "Writing this to a file.n";
myfile<<"Hope fine”" << endl;
myfile<<"this frist file ”" << endl;
myfile.close();
return 0; }
28

29. #include <fstream>
#include <iostream>
using namespace std;
int main()
{ char FirstName[30], LastName[30];
int Age;
char FileName[20];
cout << "Enter First Name: ";
cin >> FirstName;
cout << "Enter Last Name: ";
cin >> LastName;
cout << "Enter Age: ";
cin >> Age;
cout << "nEnter the name of the file you want to create:. .txt ";
cin >> FileName;
ofstream Students(FileName, ios::out);
Students << FirstName << "n" << LastName << "n" << Age;
cout << "nn";
return 0;
}
29

30. Write to file
#include<iostream>
#include <fstream>
using namespace std;
int main()
{ ofstream fout;
fout.open("FFFF.txt");
fout << "Asalamualikom hope fine .n"
<< "WELCOME TO GE 211 FILE SECTION PROGRAMn"
<< "HOPE TO DO WELL IN SECOND MEDTERM
EXAMn";
fout.close();
}
30

31. //Write the odd number in file
#include<iostream>
#include <fstream>
using namespace std;
int main()
{ ofstream fout;
fout.open("E:firsteee.txt");
int i,j;
for(i=2;i<30;i+=2)
{
fout<<i<<"t";
cout<<i<<"t";}
fout.close();
}
31

32. // print in file Even number 1:30
#include<iostream>
#include <fstream>
using namespace std;
int main()
{ ofstream fout;
fout.open("D:firstExa.txt");
int i,j;
for(i=1;i<30;i+=2)
fout<<i<<"t";
fout.close();
}
32

33. #include<iostream>
#include <fstream>
using namespace std;
int main()
{ofstream fout;
fout.open("ffffff2.txt");
float i,j,m,sum;
j=3;
sum=0;
for(i=1;i<=100;i++){
m=(i*i)/(j*j);
j=j+2;
sum=sum+m;}
cout<<"seque="<<sum<<endl;
fout<<"seque="<<sum<<endl;
fout.close();
}
33

34. //write equation for this series
#include<iostream>
using namespace std;
int main()
{
int i,j,m,n,sum;
sum=0;
cin>>n;
for(i=1 ;i<=n ;i++)
{
m=i*i;
sum=sum+m; }
cout<< "seque="<<sum<< endl;
}
34

35. #include<iostream> // using both file and screen
#include <fstream>
using namespace std;
int main()
{
ofstream fout;
fout.open("xxxx.txt");
int i,j,m,n,sum;
sum=0;
cout<<"equation for this series ="<<endl;
cin>>n;
for(i=1 ;i<=n ;i++)
{
m=i*i;
sum=sum+m; }
cout<< "seque="<<sum<< endl;
fout<< "seque= written in file is="<<sum<< endl;
fout.close();
}
35

36. #include<iostream>
#include <fstream>
#include<cmath>
using namespace std;
int main()
{
float i,m,n,b,a,y,x,s;
y=0;
b=2;
cout<<"enter the last power ofn";
cin>>n;
cout<<"enter the volue of(x)n";
cin>>s;
for(i=1;i<=n;i++){
x=pow(s,i);
a=pow(b,i);
m=x/a;
y=y+m;
}
cout<<"y= "<<y;
}
36

37. #include<iostream>
#include <fstream>
#include<cmath>
using namespace std;
main()
{ofstream fout;
fout.open("D:UUUU.txt");
float i,m,n,b,a,y,x,s;
y=0;
b=2;
cout<<"enter the last power ofn";
cin>>n;
cout<<"enter the volue of(x)n";
cin>>s;
for(i=1;i<=n;i++){
x=pow(s,i);
a=pow(b,i);
m=x/a;
y=y+m;
}
cout<<"y= "<<y;
fout<<"y= "<<y;
fout.close();
}
37

38. //Fenonci seris
#include<iostream>
#include <fstream>
using namespace std;
main()
{ofstream fout;
fout.open("finoncy.txt");
int i,s,b,d ;
s=0;
d=1;
for(i=0;i<20;i++)
{
b=s;
s=d;
d=s+b;
fout<<d<<"t";
}
fout.close();
}
38

39. #include <fstream>// Read from file
#include <iostream>
using namespace std;
int main( )
{ /*cout<<"Exam1n";
ifstream ;// read
ofstream ;// write
fstream;//read &write*/
ifstream myfile;
myfile.open("finoncy.txt");
//myfile<< "Exam1 is okn";
//myfile<< "please tray good in second exam";
cout<<myfile.rdbuf();
myfile.close();
return 0;
}
39

40. //write to file
#include<iostream>
#include <fstream>
using namespace std;
int main()
{
ofstream fout;
fout.open("D:Seris.txt");
int i,j,m,n,sum;
sum=0;
cin>>n;
for(i=1 ;i<=n ;i++)
{
m=i*i;
sum=sum+m; }
fout<< "seque="<<sum<< endl;
fout.close();
}
40

41. Read from file
#include <fstream>
#include <iostream>
using namespace std;
int main()
{ char array [80];
ifstream fin;
fin.open("firstExa.txt");
while(!fin.eof())
{fin.getline(array,80);
cout<<array<<endl;}
fin.close();
}
41

42. Write in binary file
ofstream fout ;
fout.open("file path",iostream family
fout.write((char*)& data ,sizeo(data);
42

43. Binary form
#include<iostream.h>
#include <fstream.h>
main()
{ int Array[80],i;
for(i=0;i<10;i++)
cin>> Array[i];
ofstream fout;
fout.open("D:ahmed.bin",ios::binary);
fout .write((char *) & Array , sizeof(Array));
fout.close();
system("pause");
}
43

44. // writing on a text file
#include <iostream>
#include <fstream>
using namespace 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;
}
Slide 6- 44

45. // reading a text file
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main () {
string line;
ifstream myfile ("example.txt");
if (myfile.is_open())
{
while ( myfile.good() )
{
getline (myfile,line);
cout << line << endl;
}
myfile.close();
}
else cout << "Unable to open file";
return 0;
}
Slide 6- 45

46. Using fout
Slide 6- 46
#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;
int main (int aaa,char *avg[])
{
ofstream fout ("my_out.txt");
fout<<" Assalamualikom Hope fine" << endl;
fout<<"Please tray good in second exam this frist file " << endl;
return 0;}

47. Write in file
#include <fstream>
#include <iostream>
using namespace std;
int main( )
{
//cout<<"Exam1n";
// ifstream ;// read
// ofstream ;// write
// fstream;//read &write
ofstream myfile;
myfile.open("kkkk.txt");
myfile<< "Exam1 is okn";
myfile<< "please tray good in second exam";
myfile.close();
return 0;
}
47

48. Using app
#include <fstream>
#include <iostream>
using namespace std;
int main( )
{
/*cout<<"Exam1n";
ifstream ;// read
ofstream ;// write
fstream;//read &write*/
fstream myfile;
myfile.open("kkkk.txt",ios ::out|ios::app);
//myfile<< "Exam1 is okn";
myfile<< "please tray good in second exam****************n";
//cout<<myfile.rdbuf();
myfile.close();
return 0;
}
48

49. Read from file
#include <fstream>
#include <iostream>
using namespace std;
int main( )
{
/*cout<<"Exam1n";
ifstream ;// read
ofstream ;// write
fstream;//read &write*/
ifstream myfile;
myfile.open("kkkk.txt");
//myfile<< "Exam1 is okn";
//myfile<< "please tray good in second exam";
cout<<myfile.rdbuf();
myfile.close();
system("pause");
return 0;
}
49

50. Reading from file
#include<iostream>
#include<fstream>
using namespace std;
int main()
{
char m;
int i;
double j;
ifstream fin("data.txt");
fin >> m >> i >> j;
cout << m << endl
<< i << endl
<< j << endl ;
fin.close();} 50

51. // basic file operations
#include <iostream>
#include <fstream>
using namespace std;
int main () {
ofstream myfile;
myfile.open ("example.txt");
myfile << "Writing this to a file.n";
myfile.close();
return 0;
}
51

52. class default mode parameter
ofstream ios::out
ifstream ios::in
fstream ios::in | ios::out
ofstream myfile;
myfile.open ("example.bin", ios::out | ios::app |
ios::binary);
52

53. Basic file operations
// basic file operations
#include <iostream>
#include <fstream>
//#include <ifstream>
//#include <ofstream>
using namespace std;
int main () {
ofstream myfile;
myfile.open ("XXX.txt");
myfile << "**Writing this to a file.n";
myfile << "****Writing this to a file.n";
myfile << "*********Writing this to a file.n";
myfile.close();
system("PAUSE");
return 0;
}
53

54. Basic file operations
#include <iostream>
#include <fstream>
using namespace std;
int main (int argc, char *arvg[ ])
{
ofstream fout("XXX.txt");
fout << "**Writing this to a file.n";
fout << "****Writing this to a file.n";
fout << "*********Writing this to a file.n";
system("PAUSE");
return EXIT_SUCCESS;
}
54

55. Read from file
#include <fstream>
#include <iostream>
using namespace std;
int main( )
{
/*cout<<"Exam1n";
ifstream ;// read
ofstream ;// write
fstream;//read &write*/
ifstream myfile;
myfile.open("finoncy.txt");
//myfile<< "Exam1 is okn";
//myfile<< "please tray good in second exam";
cout<<myfile.rdbuf();
myfile.close();
return 0;
}
55

56. // reading a text file
#include <iostream>
#include <fstream>
#include <stdlib.h>
using namespace std;
int main () {
char buffer[256];
ifstream examplefile ("kk.txt");
if (! examplefile.is_open())
{ cout << "Error opening file"; exit (1); }
while (! examplefile.eof() )
{
examplefile.getline (buffer,100);
cout << buffer << endl;
}
return 0;
} 56

57. // writing on a text file
#include <iostream>
#include <fstream>
using namespace 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;
}
57