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/* Sample implementation of wc utility. */
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
typedef unsigned long count_t; /* Counter type */
/* Current file counters: chars, words, lines */
count_t ccount;
count_t wcount;
count_t lcount;
/* Totals counters: chars, words, lines */
count_t total_ccount = 0;
count_t total_wcount = 0;
count_t total_lcount = 0;
/* Print error message and exit with error status. If PERR is not 0,
 display current errno status. */
static void
error_print (int perr, char *fmt, va_list ap)
{
 vfprintf (stderr, fmt, ap);
 if (perr)
 perror (" ");
 else
 fprintf (stderr, "\n");
 exit (1); 
}
/* Print error message and exit with error status. */
static void
errf (char *fmt, ...)
{
 va_list ap;
 
 va_start (ap, fmt);
 error_print (0, fmt, ap);
 va_end (ap);
}
/* Print error message followed by errno status and exit
 with error code. */
static void
perrf (char *fmt, ...)
{
 va_list ap;
 
 va_start (ap, fmt);
 error_print (1, fmt, ap);
 va_end (ap);
}
/* Output counters for given file */
void
report (char *file, count_t ccount, count_t wcount, count_t lcount)
{
 printf ("%6lu %6lu %6lu %s\n", lcount, wcount, ccount, file);
}
/* Return true if C is a valid word constituent */
static int
isword (unsigned char c)
{
 return isalpha (c);
}
/* Increase character and, if necessary, line counters */
#define COUNT(c) \
 ccount++; \
 if ((c) == '\n') \
 lcount++;
/* Get next word from the input stream. Return 0 on end
 of file or error condition. Return 1 otherwise. */
int
getword (FILE *fp)
{
 int c;
 int word = 0;
 
 if (feof (fp))
 return 0;
 
 while ((c = getc (fp)) != EOF)
 {
 if (isword (c))
 {
 wcount++;
 break;
 }
 COUNT (c);
 }
 for (; c != EOF; c = getc (fp))
 {
 COUNT (c);
 if (!isword (c))
 break;
 }
 return c != EOF;
}
 
/* Process file FILE. */
void
counter (char *file)
{
 FILE *fp = fopen (file, "r");
 
 if (!fp)
 perrf ("cannot open file `%s'", file);
 ccount = wcount = lcount = 0;
 while (getword (fp))
 ;
 fclose (fp);
 report (file, ccount, wcount, lcount);
 total_ccount += ccount;
 total_wcount += wcount;
 total_lcount += lcount;
}
 
int
main (int argc, char **argv)
{
 int i;
 
 if (argc < 2)
 errf ("usage: wc FILE [FILE...]");
 
 for (i = 1; i < argc; i++)
 counter (argv[i]);
 
 if (argc > 2)
 report ("total", total_ccount, total_wcount, total_lcount);
 return 0;
}