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1.1 root 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 are permitted
6: * provided that the above copyright notice and this paragraph are
7: * duplicated in all such forms and that any documentation,
8: * advertising materials, and other materials related to such
9: * distribution and use acknowledge that the software was developed
10: * by the University of California, Berkeley. The name of the
11: * University may not be used to endorse or promote products derived
12: * from this software without specific prior written permission.
13: * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14: * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15: * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16: */
17:
18: #ifndef lint
19: static char sccsid[] = "@(#)extra.c 5.3 (Berkeley) 6/18/88";
20: #endif /* not lint */
21:
22: #include "back.h"
23:
24: #ifdef DEBUG
25: #include <stdio.h>
26: FILE *trace;
27: #endif
28:
29: /*
30: * dble()
31: * Have the current player double and ask opponent to accept.
32: */
33:
34: dble () {
35: register int resp; /* response to y/n */
36:
37: for (;;) {
38: writel (" doubles."); /* indicate double */
39:
40: if (cturn == -pnum) { /* see if computer accepts */
41: if (dblgood()) { /* guess not */
42: writel (" Declined.\n");
43: nexturn();
44: cturn *= -2; /* indicate loss */
45: return;
46: } else { /* computer accepts */
47: writel (" Accepted.\n");
48: gvalue *= 2; /* double game value */
49: dlast = cturn;
50: if (tflag)
51: gwrite();
52: return;
53: }
54: }
55:
56: /* ask if player accepts */
57: writel (" Does ");
58: writel (cturn == 1? color[2]: color[3]);
59: writel (" accept?");
60:
61: /* get response from yorn,
62: * a "2" means he said "p"
63: * for print board. */
64: if ((resp = yorn ('R')) == 2) {
65: writel (" Reprint.\n");
66: buflush();
67: wrboard();
68: writel (*Colorptr);
69: continue;
70: }
71:
72: /* check response */
73: if (resp) {
74: /* accepted */
75: gvalue *= 2;
76: dlast = cturn;
77: if (tflag)
78: gwrite();
79: return;
80: }
81:
82: nexturn (); /* declined */
83: cturn *= -2;
84: return;
85: }
86: }
87:
88: /*
89: * dblgood ()
90: * Returns 1 if the computer would double in this position. This
91: * is not an exact science. The computer will decline a double that he
92: * would have made. Accumulated judgments are kept in the variable n,
93: * which is in "pips", i.e., the position of each man summed over all
94: * men, with opponent's totals negative. Thus, n should have a positive
95: * value of 7 for each move ahead, or a negative value of 7 for each one
96: * behind.
97: */
98:
99: dblgood () {
100: register int n; /* accumulated judgment */
101: register int OFFC = *offptr; /* no. of computer's men off */
102: register int OFFO = *offopp; /* no. of player's men off */
103:
104: #ifdef DEBUG
105: register int i;
106: if (trace == NULL)
107: trace = fopen ("bgtrace","w");
108: #endif
109:
110: /* get real pip value */
111: n = eval()*cturn;
112: #ifdef DEBUG
113: fputs ("\nDoubles:\nBoard: ",trace);
114: for (i = 0; i < 26; i++)
115: fprintf (trace," %d",board[i]);
116: fprintf (trace,"\n\tpip = %d, ",n);
117: #endif
118:
119: /* below adjusts pip value
120: * according to position
121: * judgments */
122:
123: /* check men moving off
124: * board */
125: if (OFFC > -15 || OFFO > -15) {
126: if (OFFC < 0 && OFFO < 0) {
127: OFFC += 15;
128: OFFO += 15;
129: n +=((OFFC-OFFO)*7)/2;
130: } else if (OFFC < 0) {
131: OFFC += 15;
132: n -= OFFO*7/2;
133: } else if (OFFO < 0) {
134: OFFO += 15;
135: n += OFFC*7/2;
136: }
137: if (OFFC < 8 && OFFO > 8)
138: n -= 7;
139: if (OFFC < 10 && OFFO > 10)
140: n -= 7;
141: if (OFFC < 12 && OFFO > 12)
142: n -= 7;
143: if (OFFO < 8 && OFFC > 8)
144: n += 7;
145: if (OFFO < 10 && OFFC > 10)
146: n += 7;
147: if (OFFO < 12 && OFFC > 12)
148: n += 7;
149: n += ((OFFC-OFFO)*7)/2;
150: }
151:
152: #ifdef DEBUG
153: fprintf (trace,"off = %d, ",n);
154: #endif
155:
156: /* see if men are trapped */
157: n -= freemen(bar);
158: n += freemen(home);
159: n += trapped(home,-cturn);
160: n -= trapped(bar,cturn);
161:
162: #ifdef DEBUG
163: fprintf (trace,"free = %d\n",n);
164: fprintf (trace,"\tOFFC = %d, OFFO = %d\n",OFFC,OFFO);
165: fflush (trace);
166: #endif
167:
168: /* double if 2-3 moves ahead */
169: if (n > 10+rnum(7))
170: return(1);
171: return (0);
172: }
173:
174: freemen (b)
175: int b;
176:
177: {
178: register int i, inc, lim;
179:
180: odds(0,0,0);
181: if (board[b] == 0)
182: return (0);
183: inc = (b == 0? 1: -1);
184: lim = (b == 0? 7: 18);
185: for (i = b+inc; i != lim; i += inc)
186: if (board[i]*inc < -1)
187: odds(abs(b-i),0,abs(board[b]));
188: if (abs(board[b]) == 1)
189: return ((36-count())/5);
190: return (count()/5);
191: }
192:
193: trapped (n,inc)
194: int n, inc;
195:
196: {
197: register int i, j, k;
198: int c, l, ct;
199:
200: ct = 0;
201: l = n+7*inc;
202: for (i = n+inc; i != l; i += inc) {
203: odds (0,0,0);
204: c = abs(i-l);
205: if (board[i]*inc > 0) {
206: for (j = c; j < 13; j++)
207: if (board[i+inc*j]*inc < -1) {
208: if (j < 7)
209: odds (j,0,1);
210: for (k = 1; k < 7 && k < j; k++)
211: if (j-k < 7)
212: odds (k,j-k,1);
213: }
214: ct += abs(board[i])*(36-count());
215: }
216: }
217: return (ct/5);
218: }
219:
220: eval () {
221:
222: register int i, j;
223:
224: for (j = i = 0; i < 26; i++)
225: j += (board[i] >= 0 ? i*board[i] : (25-i)*board[i]);
226:
227: if (off[1] >= 0)
228: j += 25*off[1];
229: else
230: j += 25*(off[1]+15);
231:
232: if (off[0] >= 0)
233: j -= 25*off[0];
234: else
235: j -= 25*(off[0]+15);
236: return (j);
237: }
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