/*
av.c Joe Mietus Dec 19 2001
-------------------------------------------------------------------------------
av: Reads stdin and outputs n, av, and sd of data
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/).
_______________________________________________________________________________
Usage : av
Reads stdin and outputs n, av, and sd of data
*/
#include <stdio.h>
#include <math.h>
main(argc, argv)
int argc;
char *argv[];
{
int cnt;
double n, sum, sum2;
double av, var, sd;
if (argc != 1) {
usage(argv[0]);
exit(1);
}
cnt = 0;
sum = sum2 = 0.;
while (scanf("%lf", &n) == 1) {
cnt++;
sum += n;
sum2 += n*n;
}
av = sum/cnt;
var = (sum2 - sum*sum/cnt) / (cnt-1);
sd = sqrt(var);
printf("%d %g %g\n", cnt, av, sd);
}
usage(prog)
char *prog;
{
fprintf(stderr, "Usage : %s\n\n", prog);
fprintf(stderr, " Reads stdin and outputs n, av, and sd of data\n");
}