File in cpp 2016

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

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

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

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>

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
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:

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

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

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
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

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);

FLAGES IN FILE
FLAGES IN FILE
17

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

// 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;
}
19

Writing to file
#include <iostream>
#include <fstream>
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

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

// writing in file
#include<iostream> //divide by 7
#include <fstream>
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

#include<iostream>//prime number
#include<fstream>
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

#include<iostream>// !x=x*(x-1)*(x-2)….
#include<fstream>
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
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”;
}

// writing on a text file
#include <iostream>
#include <fstream>
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

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

#include <fstream>
#include <iostream>
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

Write to file
#include<iostream>
#include <fstream>
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

//Write the odd number in file
#include<iostream>
#include <fstream>
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

// print in file Even number 1:30
#include<iostream>
#include <fstream>
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

#include<iostream>
#include <fstream>
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

//write equation for this series
#include<iostream>
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

#include<iostream> // using both file and screen
#include <fstream>
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

#include<iostream>
#include <fstream>
#include<cmath>
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

#include<iostream>
#include <fstream>
#include<cmath>
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

//Fenonci seris
#include<iostream>
#include <fstream>
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

#include <fstream>// Read from file
#include <iostream>
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

//write to file
#include<iostream>
#include <fstream>
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

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

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

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

#include <iostream>
#include <fstream>
int main () {
ofstream myfile ("example.txt");
{
myfile << "This is a line.n";
myfile.close();
}
return 0;
}
Slide 6- 44

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

Using fout
Slide 6- 46
#include <iostream>
#include <fstream>
#include <cstdlib>
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;}

Write in file
#include <fstream>
#include <iostream>
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

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

Read from file
#include <fstream>
#include <iostream>
int main( )
{
/*cout<<"Exam1n";
ifstream ;// read
ofstream ;// write
ifstream myfile;
myfile.open("kkkk.txt");
myfile.close();
system("pause");
return 0;
}
49

Reading from file
#include<iostream>
#include<fstream>
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

// basic file operations
#include <iostream>
#include <fstream>
int main () {
ofstream myfile;
myfile.open ("example.txt");
myfile.close();
return 0;
}
51

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

Basic file operations
// basic file operations
#include <iostream>
#include <fstream>
//#include <ifstream>
//#include <ofstream>
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

Basic file operations
#include <iostream>
#include <fstream>
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

Read from file
#include <fstream>
#include <iostream>
int main( )
{
/*cout<<"Exam1n";
ifstream ;// read
ofstream ;// write
ifstream myfile;
myfile.open("finoncy.txt");
myfile.close();
return 0;
}
55

// reading a text file
#include <iostream>
#include <fstream>
#include <stdlib.h>
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

#include <iostream>
#include <fstream>
int main () {
ofstream myfile ("example.txt");
{
myfile << "This is a line.n";
myfile.close();
}
return 0;
}
57

File in cpp 2016

Recommandé

Recommandé

Contenu connexe

Tendances

Tendances (20)

En vedette

En vedette (12)

Similaire à File in cpp 2016

Similaire à File in cpp 2016 (20)

Dernier

Dernier (20)

File in cpp 2016