toys/seq.c

/* vi: set sw=4 ts=4:
 *
 * seq.c - Count from first to last, by increment.
 *
 * Copyright 2006 Rob Landley <rob@landley.net>
 *
 * Not in SUSv3.  (Don't ask me why not.)

USE_SEQ(NEWTOY(seq, "<1>3?", TOYFLAG_USR|TOYFLAG_BIN))

config SEQ
	bool "seq"
	default y
	help
	  usage: seq [first] [increment] last

	  Count from first to last, by increment.  Omitted arguments default
	  to 1.  Two arguments are used as first and last.  Arguments can be
	  negative or floating point.
*/

#include "toys.h"

void seq_main(void)
{
	double first, increment, last, dd;

	// Parse command line arguments, with appropriate defaults.
	// Note that any non-numeric arguments are treated as zero.
	first = increment = 1;
	switch (toys.optc) {
		case 3:
			increment = atof(toys.optargs[1]);
		case 2:
			first = atof(*toys.optargs);
		default:
			last = atof(toys.optargs[toys.optc-1]);
	}

	// Yes, we're looping on a double.  Yes rounding errors can accumulate if
	// you use a non-integer increment.  Deal with it.
	for (dd=first; (increment>0 && dd<=last) || (increment <0 && dd>=last);
		dd+=increment)
	{
		printf("%g\n", dd);
	}
}