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

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

3. Table 12-1

4. Figure 1-1

5. Figure 1-2

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

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
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.

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. 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

13. 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.

14. Functions use in File Handling
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.

15. 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
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();

16. File Opening mode Example fstream file;
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
take us to the end of the file when it is opened.
Example
fstream file;
file.Open("data . txt", ios :: out | ios :: in);

17. FLAGES IN FILE
FLAGES IN FILE

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.close();
return 0; }

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 Completed\n";
return 0; }

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

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

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;

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;

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

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
#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;

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; }

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 << "\n\n";
return 0; }

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 PROGRAM\n"
<< "HOPE TO DO WELL IN SECOND MEDTERM EXAM\n";
fout.close(); }

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(); }

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

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(); }

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; }

35. #include<iostream>
#include <fstream>
using namespace std;
int main() {
ofstream fout;
fout.open("ffff00.txt");
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;
fout<< "seque="<<sum<< endl;
fout.close(); }

36. #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(); }

37. #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 of\n";
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;

38. #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 of\n";
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();

39. //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();

40. //write to file
#include<iostream>
#include <fstream>
using namespace std;
int main() {
ofstream fout;
fout.open(“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(); }

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(); }

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

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"); }

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;

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;

46. Using fout #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<<"Exam1\n";
// ifstream ;// read
// ofstream ;// write
// fstream;//read &write
ofstream myfile;
myfile.open("kkkk.txt");
myfile<< "Exam1 is ok\n";
myfile<< "please tray good in second exam";
myfile.close();
return 0; }

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

49. Read from file #include <fstream> #include <iostream>
using namespace std;
int main( ) {
ifstream myfile;
myfile.open("kkkk.txt");
//myfile<< "Exam1 is ok\n";
//myfile<< "please tray good in second exam";
cout<<myfile.rdbuf();
myfile.close(); }

50. Reading from file #include<iostream> #include<fstream>
using namespace std;
int main()
{ char m;
int i;
double j;
ifstream fin("data.txt");// enter k,5,9.8
fin >> m >> i >> j;
cout << m << endl << i << endl<< j << endl ;
fin.close();}

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; }

52. myfile.open ("example.bin", ios::out | ios::app | ios::binary);
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);

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();
return 0; }

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";
return EXIT_SUCCESS; }

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

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;

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;