File Handling

File Handling concept in C language is used for store a data permanently in computer. Using this concept we can store our data in Secondary memory (Hard disk). All files related function are available in stdio.h header file.

How to achieve File Handling in C

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

Functions use in File Handling in C

S.No	Function	Operation
1	fopen()	To create a file
2	fclose()	To close an existing file
3	getc()	Read a character from a file
4	putc()	Write a character in file
5	fprintf()	To write set of data in file
6	fscanf()	To read set of data from file.
5	getw()	To read an integer from a file
6	putw()	To write an integer in file

Defining and Opening a File

Data structure of file is defined as FILE in the standard I/O function. So all files should be declared as type FILE.

Before opening any file we need to specify for which purpose we open file, for example file open for write or read purpose.

Syntax

FILE *fp;
pf=fopen("filename", "mode");

Here fp declare a variable as a pointer to the data type FILE.

Closing a File

A file must be close after completion of all operation related to file. For closing file we need fclose() function.

Syntax

fclose(Filepointer);

File Opening mode

S.No	Mode	Meaning	Purpose
1	r	Reading	Open the file for reading only.
2	w	Writing	Open the file for writing only.
3	a	Appending	Open the file for appending (or adding) data to it.
4	r+	Reading + Writing	New data is written at the beginning override existing data.
5	w+	Writing + Reading	Override existing data.
6	a+	Reading + Appending	To new data is appended at the end of file.

Input/Output Operation on files

To perform Input/Output Operation on files we need below functions.

S.No	Function	Operation	Syntax
1	getc()	Read a character from a file	getc( fp)
2	putc()	Write a character in file	putc(c, fp)
3	fprintf()	To write set of data in file	fprintf(fp, "control string", list)
4	fscanf()	To read set of data from file.	fscanf(fp, "control string", list)
5	getw()	To read an integer from a file.	getw(fp)
6	putw()	To write an integer in file.	putw(integer, fp)

Write data in File

Example

#include<stdio.h>
#include<conio.h>

void main()
{
FILE *fp;
char ch[20];
clrscr();
fp=fopen("hh.txt", "w");
printf("Enter any Text: ");
scanf("%s",&ch); // Read data from keyboard
fprintf(fp,"%s",ch); // Write data in file
fclose(fp);
getch();
}

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