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odds.c revision 1.2 
      1 /*
      2  * Copyright (c) 1980 Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #ifndef lint
     35 /*static char sccsid[] = "from: @(#)odds.c	5.4 (Berkeley) 6/1/90";*/
     36 static char rcsid[] = "$Id: odds.c,v 1.2 1993/08/01 18:56:42 mycroft Exp $";
     37 #endif /* not lint */
     38 
     39 #include "back.h"
     40 
     41 odds (r1,r2,val)
     42 register int	r1;
     43 int		r2, val;
     44 {
     45 	register int	i, j;
     46 
     47 	if (r1 == 0)  {
     48 		for (i = 0; i < 6; i++)
     49 			for (j = 0; j < 6; j++)
     50 				table[i][j] = 0;
     51 		return;
     52 	} else  {
     53 		r1--;
     54 		if (r2-- == 0)
     55 			for (i = 0; i < 6; i++)  {
     56 				table[i][r1] += val;
     57 				table[r1][i] += val;
     58 			}
     59 		else  {
     60 			table[r2][r1] += val;
     61 			table[r1][r2] += val;
     62 		}
     63 	}
     64 }
     65 
     66 count ()  {
     67 	register int	i;
     68 	register int	j;
     69 	register int	total;
     70 
     71 	total = 0;
     72 	for (i = 0; i < 6; i++)
     73 		for (j = 0; j < 6; j++)
     74 			total += table[i][j];
     75 	return (total);
     76 }
     77 
     78 canhit (i,c)
     80 int	i, c;
     81 
     82 {
     83 	register int	j, k, b;
     84 	int		a, d, diff, place, addon, menstuck;
     85 
     86 	if (c == 0)
     87 		odds (0,0,0);
     88 	if (board[i] > 0)  {
     89 		a = -1;
     90 		b = 25;
     91 	} else  {
     92 		a = 1;
     93 		b = 0;
     94 	}
     95 	place = abs (25-b-i);
     96 	menstuck = abs (board[b]);
     97 	for (j = b; j != i; j += a)  {
     98 		if (board[j]*a > 0)  {
     99 			diff = abs(j-i);
    100 			addon = place+((board[j]*a > 2 || j == b)? 5: 0);
    101 			if ((j == b && menstuck == 1) &&
    102 			    (j != b && menstuck == 0))
    103 				for (k = 1; k < diff; k++)
    104 					if (k < 7 && diff-k < 7 &&
    105 					    (board[i+a*k]*a >= 0 ||
    106 					    board[i+a*(diff-k)] >= 0))
    107 						odds (k,diff-k,addon);
    108 			if ((j == b || menstuck < 2) && diff < 7)
    109 				odds (diff,0,addon);
    110 		}
    111 		if (j == b && menstuck > 1)
    112 			break;
    113 	}
    114 	return (count());
    115 }
    116