/*

smooth.c		Joe Mietus		Dec 19 2001

-------------------------------------------------------------------------------
smooth: Smooth two column stdin with a sliding window average.
Copyright (C) 2002 Joe Mietus

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA.

You may contact the author by e-mail (joe at physionet dot org) or postal mail
(MIT Room E25-505A, Cambridge, MA 02139 USA).  For updates to this software,
please visit PhysioNet (http://www.physionet.org/).
_______________________________________________________________________________

Smooth two column stdin with a sliding window average.

Usage : smooth window
*/

#include <stdio.h>

#define MAXWIN	7200


main(argc, argv)
int argc;
char *argv[];
{
    int i, win;
    static double x[MAXWIN], y[MAXWIN];
    double sumx, sumy;


    if (argc < 2) {
        usage(argv[0]);
	exit(1);
    }

    if ((win = atoi(argv[1])) <= 1) {
	fprintf(stderr, "%s : maximum window size must be greater than 1\n", argv[0]);
	exit(2);
    }
    else if (win > MAXWIN) {
	fprintf(stderr, "%s : maximum window size is %d\n", argv[0], MAXWIN);
	exit(2);
    }

    sumx = sumy = 0.0;

    for (i=0;  i<win && scanf("%lf %lf", &x[i], &y[i]) == 2; i++) {
        sumx += x[i];
        sumy += y[i];
    }

    if (i < win) {
        fprintf(stderr, "%s : not enough points in input\n", argv[0]);
	exit(2);
    }

    printf("%g %g\n", sumx/win, sumy/win);

    i = 0;
    sumx -= x[i];
    sumy -= y[i];

    while (scanf("%lf %lf", &x[i], &y[i]) == 2) {

        sumx += x[i];
        sumy += y[i];

        printf("%g %g\n", sumx/win, sumy/win);

	if (++i >= win)
	    i = 0;
        sumx -= x[i];
        sumy -= y[i];

    }

}


usage(prog)
char *prog;
{
	fprintf(stderr, "Usage : %s window\n\n", prog);
	fprintf(stderr, " Smooth two column stdin with  sliding window average.\n");
}