source: ttyvaders/trunk/src/math.c @ 44

Last change on this file since 44 was 44, checked in by Sam Hocevar, 18 years ago
  • Removed the dependency on <math.h>. We don't need no stinking sqrt!
File size: 1.2 KB
Line 
1/*
2 *   ttyvaders     Textmode shoot'em up
3 *   Copyright (c) 2002 Sam Hocevar <sam@zoy.org>
4 *                 All Rights Reserved
5 *
6 *   $Id: math.c,v 1.1 2002/12/22 22:36:42 sam Exp $
7 *
8 *   This program is free software; you can redistribute it and/or modify
9 *   it under the terms of the GNU General Public License as published by
10 *   the Free Software Foundation; either version 2 of the License, or
11 *   (at your option) any later version.
12 *
13 *   This program is distributed in the hope that it will be useful,
14 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
15 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16 *   GNU General Public License for more details.
17 *
18 *   You should have received a copy of the GNU General Public License
19 *   along with this program; if not, write to the Free Software
20 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23#include "common.h"
24
25int r00t( int a )
26{
27    int x = a > 100000 ? 1000 : a > 1000 ? 100 : a > 10 ? 10 : 1;
28
29    /* Newton's method. Three iterations are more than enough. */
30    x = (x * x + a) / x / 2;
31    x = (x * x + a) / x / 2;
32    x = (x * x + a) / x / 2;
33    x = (x * x + a) / x / 2;
34
35    return x;
36}
37
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