The Standard I/O Library
provides similar routines for file I/O to those used for standard I/O.
The
routine getc(fp) is similar to getchar()
and
putc(c,fp) is similar to putchar(c).
Thus
the statement
c = getc(fp);
reads
the next character from the file referenced by fp and the statement
putc(c,fp);
writes
the character c into file referenced by fp.
Basic Program me:-
/*
file.c: Display contents of a file on screen */
#include
<stdio.h>
void
main()
{
FILE *fopen(), *fp;
int c ;
fp = fopen( “prog.c”, “r” );
c = getc( fp ) ;
while ( c != EOF )
{
putchar( c );
c = getc ( fp );
}
fclose( fp );
}
Description:-
In
this program, we open the file prog.c for reading.
We
then read a character from the file. This file must exist for this program to
work.
If
the file is empty, we are at the end, so getc returns EOF a special value to
indicate that the end of file has been reached. (Normally -1 is used for EOF)
The
while loop simply keeps reading characters from the file and displaying them,
until the end of the file is reached.
The
function fclose is used to close
the file i.e. indicate that we are finished processing this file.
We
could reuse the file pointer fp by opening another file.
This
program is in effect a special purpose cat command. It displays file contents
on the screen, but only for a file
called prog.c.
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