File Management

File Management

File Handling

There are two types of streams: text and binary

Text Streams:
A Text stream is a sequence of characters.
Standard C states that a text stream is organized into lines terminated by a newline character.

Binary Streams:
A Binary stream is a sequence of bytes that has a one-to-one correspondence to the bytes in the external device— that is, no character translations occur.

fopen() :

fopen() is used for opening a file.

Syntex :
FILE *fopen(const char *filename, const char *mode);

Example:
FILE *fp;
fp = fopen("test", "w");

The modes used with fopen() :

r       - Open a text file for reading
w      - Create a text file for writing
a      - Append to a text file
rb     - Open a binary file for reading
wb   - Create a binary file for writing
ab    - Append to a binary file
r+    - Open a text file for read/write
w+   - Create a text file for read/write
a+   -  Append or create a text file for read/write
r+b  - Open a binary file for read/write
w+b - Create a binary file for read/write
a+b -  Append or create a binary file for read/write

fseek():

Repositions the file pointer of a stream
You can perform random read and write operations using the C I/O system with the help of fseek( ),which sets the file position indicator.

Syntax:
int fseek(FILE *fp, long int numbytes, int origin);

Example:

FILE *fp;
fp=fopen("D:/student.txt","r");
fseek(*fp,0L,SEEK_SET);

ftell( ):

Returns the current file pointer
You can determine the current location of a file using ftell( ).

Syntax:
long int ftell(FILE *fp);

Example:
FILE *fp;
int i;
Fp=fopen("D:/student.txt","r");
i=ftell(fp);

feof( ) :

The feof( ) function determines whether the end of the file associated with
the stream has been reached.

Syntax:
int feof(FILE *stream);

Example:
while(!feof(fp))
{
getc(fp);
}

fread( ) :
fread( ) functions allow the reading of blocks of any type of data.

Syntax:
size_t fread(void *buffer, size_t num_bytes, size_t count, FILE *fp);

fwrite( ) :
fwrite( ) functions allow the writing of blocks of any type of data.

Syntax:
size_t fwrite(const void *buffer, size_t num_bytes, size_t count, FILE *fp);