FILE HANDLING IN C:-

File & Directory:-

File is a mechanism which stores data and Directory is a mechanism which stores file.

Types of File:-

Regular File
Directory FIle
FIFO File
Socket File
Link File
Character special File
Block special File

The maximum size of the file depends upon the file system such as

Windows:-
FAT32-4GB
NTFS-more than 4GB

MS-DOS:-
FAT 16 -64kb

Different file operation and their standard library function:-

file operation                                                     Standard library function
—————                                                       ——————————
Open a file                                                                         fopen()
Close a file                                                                         fclose()
Remove a file                                                                    fremove()
Rename a file                                                                    frename()
Transfer control to the beginning of a file                  rewind()
Transfer control to any position of a file                     fseek()
Write a character into a file                                           putc()
Read a character from a file                                          getc()
Write a word into a file                                                   putw()
Read a word from a file                                                  getw()
Write a string into a file                                                 fputs()
Read a string in a file                                                      fgets()
Write a structure/records into a file                            fwrite()
Read a structure/records from a file                           fread()
Write a formatted data into a file                                 fprintf()
Read formatted data from a file                                   fscanf()

File Opening mode:-

Write mode       “w”
Append mode    “a”
Read mode         “r”

Write Mode:-

Create a new file if not exists, if exists delete the contains of the file. It is also called truncated.

Append Mode:-

Create a new file if not exists, if exists then doesn’t delete the contains of the file.

Read Mode:-

Read mode only read the character.

Measure difference between write mode and append mode:-

Write mode file is truncated but append mode file is not truncated.

PROGRAM:-
FILE IS PRESENT OF NOT PRESENT
#include"stdio.h"
main()
{
FILE *p,*q;
char x;
p=fopen("/home/litindia/Desktop/letter.txt","r");
if(p==0)
{
printf("file is not found");
return;
}
else
{
printf("File is present");
}
}

PROGRAM:-
READ THE CONTAINS OF THE FILE
#include"stdio.h"
main()
{
FILE *p,*q;
char X;
p=fopen("/home/litindia/Desktop/letter.txt","r");
if(p==0)
{
printf("file is not found");
return;
}
else
{
while((X=getc(p))!=EOF)
{
printf("%c",X);
}
}
}

PROGRAM:-
COPY THE CONTAINS OF FILE INTO ANOTHER FILE
#include"stdio.h"
main()
{
FILE *p,*q;
char x;
p=fopen("/home/litindia/Desktop/letter.txt","r");
q=fopen("/home/litindia/Desktop/report.txt","w");
if(p==0)
{
printf("file is not found");
return;
}
else
{
while((x=getc(p))!=EOF)
{
putc(x,p);
}
}
}


Also Read:-Pointer in C
Also Read:-Structure Union in C
Also Read:- Function in C