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PAGER.C
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─────Run-Time Library───────────────────────────────────────────────────────
/* PAGER.C illustrates line input and output on stream text files.
* Functions illustrated include:
* fopen fclose _fcloseall feof
* fgets fputs rename
*/
#include <stdio.h>
#include <io.h>
#include <dos.h>
#include <stdlib.h>
#include <string.h>
#define MAXSTRING 128
#define PAGESIZE 55
void quit( int error );
FILE *infile, *outfile;
char outpath[] = "tmXXXXXX";
void main( int argc, char *argv[] )
{
char tmp[MAXSTRING];
long line = 0, page = 1;
/* Open file (from command line) and output (temporary) files. */
if( (infile = fopen( argv[1], "rt" )) == NULL )
quit( 1 );
_mktemp( outpath );
if( (outfile = fopen( outpath, "wt" )) == NULL )
quit( 2 );
/* Get each line from input and write to output. */
while( 1 )
{
/* Insert form feed and page header at the top of each page. */
if( !(line++ % PAGESIZE) )
fprintf( outfile, "\f\nPage %d\n\n", page++ );
if( fgets( tmp, MAXSTRING - 1, infile ) == NULL )
if( feof( infile ) )
break;
else
quit( 3 );
if( fputs( tmp, outfile ) == EOF )
quit( 3 );
}
/* Close files and move temporary file to original by deleting
* original and renaming temporary.
*/
_fcloseall();
remove( argv[1] );
rename( outpath, argv[1] );
exit( 0 );
}
/* Handles errors */
void quit( int error )
{
switch( error )
{
case 1:
perror( "Can't open input file" );
break;
case 2:
perror( "Can't open output file" );
fclose( infile );
break;
case 3:
perror( "Error processing file" );
fclose( infile );
fclose( outfile );
remove( outpath );
break;
}
exit( error );
}
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