/*
 * Convert decimal to binary.
 *
 * Written by Peter Postma <peter@pointless.nl>
 * This program is in the public domain.
 */

#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int
main(int argc, char *argv[])
{
	unsigned char s[255];
	unsigned long long c;
	char *p;
	int i;

	if (argc < 2) {
		fprintf(stderr, "usage: %s number\n", argv[0]);
		return 1;
	}

	c = strtoull(argv[1], &p, 10);
	if (*p != '\0')
		errx(1, "invalid number '%s'", argv[1]);

	for (i = 0; i < 255 && c > 0; i++) {
		s[i] = (c & 1) + 48;
		c >>= 1;
	}
	s[i] = '\0';

	for (; i >= 0; i--)
		putchar(s[i]);

	printf("\n");
	fflush(stdout);

	return 0;
}