/*
 *      swapbytes.c -- swap pairs of bytes in every group of 4 
 */
#include <stdio.h>
#include <ctype.h>

main(int argc, char **argv)
{
   int i = 0, c[4];

   if (argc <= 1) 
     while (	(c[0] = getchar()) != EOF && 
		(c[1] = getchar()) != EOF && 
		(c[2] = getchar()) != EOF && 
		(c[3] = getchar()) != EOF     ) {
	putchar(c[3]);
	putchar(c[2]);
	putchar(c[1]);
	putchar(c[0]);
	i +=4;
        }
   else if (argc == 1) {	/* file name supplied */
        printf("cannot do files for now, using stdin\n");
	}
   else {
        printf("usage: swapbytes [filename]\n");
	}
   fprintf(stderr," %d bytes processed\n",i);
}