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1.1 root 1: /*
2: * Copyright (c) 1980 Regents of the University of California.
3: * All rights reserved. The Berkeley software License Agreement
4: * specifies the terms and conditions for redistribution.
5: */
6:
7: #ifndef lint
8: static char sccsid[] = "@(#)extra.c 5.1 (Berkeley) 5/29/85";
9: #endif not lint
10:
11: #include "back.h"
12:
13: #ifdef DEBUG
14: #include <stdio.h>
15: FILE *trace;
16: #endif
17:
18: /*
19: * dble()
20: * Have the current player double and ask opponent to accept.
21: */
22:
23: dble () {
24: register int resp; /* response to y/n */
25:
26: for (;;) {
27: writel (" doubles."); /* indicate double */
28:
29: if (cturn == -pnum) { /* see if computer accepts */
30: if (dblgood()) { /* guess not */
31: writel (" Declined.\n");
32: nexturn();
33: cturn *= -2; /* indicate loss */
34: return;
35: } else { /* computer accepts */
36: writel (" Accepted.\n");
37: gvalue *= 2; /* double game value */
38: dlast = cturn;
39: if (tflag)
40: gwrite();
41: return;
42: }
43: }
44:
45: /* ask if player accepts */
46: writel (" Does ");
47: writel (cturn == 1? color[2]: color[3]);
48: writel (" accept?");
49:
50: /* get response from yorn,
51: * a "2" means he said "p"
52: * for print board. */
53: if ((resp = yorn ('R')) == 2) {
54: writel (" Reprint.\n");
55: buflush();
56: wrboard();
57: writel (*Colorptr);
58: continue;
59: }
60:
61: /* check response */
62: if (resp) {
63: /* accepted */
64: gvalue *= 2;
65: dlast = cturn;
66: if (tflag)
67: gwrite();
68: return;
69: }
70:
71: nexturn (); /* declined */
72: cturn *= -2;
73: return;
74: }
75: }
76:
77: /*
78: * dblgood ()
79: * Returns 1 if the computer would double in this position. This
80: * is not an exact science. The computer will decline a double that he
81: * would have made. Accumulated judgments are kept in the variable n,
82: * which is in "pips", i.e., the position of each man summed over all
83: * men, with opponent's totals negative. Thus, n should have a positive
84: * value of 7 for each move ahead, or a negative value of 7 for each one
85: * behind.
86: */
87:
88: dblgood () {
89: register int n; /* accumulated judgment */
90: register int OFFC = *offptr; /* no. of computer's men off */
91: register int OFFO = *offopp; /* no. of player's men off */
92:
93: #ifdef DEBUG
94: register int i;
95: if (trace == NULL)
96: trace = fopen ("bgtrace","w");
97: #endif
98:
99: /* get real pip value */
100: n = eval()*cturn;
101: #ifdef DEBUG
102: fputs ("\nDoubles:\nBoard: ",trace);
103: for (i = 0; i < 26; i++)
104: fprintf (trace," %d",board[i]);
105: fprintf (trace,"\n\tpip = %d, ",n);
106: #endif
107:
108: /* below adjusts pip value
109: * according to position
110: * judgments */
111:
112: /* check men moving off
113: * board */
114: if (OFFC > -15 || OFFO > -15) {
115: if (OFFC < 0 && OFFO < 0) {
116: OFFC += 15;
117: OFFO += 15;
118: n +=((OFFC-OFFO)*7)/2;
119: } else if (OFFC < 0) {
120: OFFC += 15;
121: n -= OFFO*7/2;
122: } else if (OFFO < 0) {
123: OFFO += 15;
124: n += OFFC*7/2;
125: }
126: if (OFFC < 8 && OFFO > 8)
127: n -= 7;
128: if (OFFC < 10 && OFFO > 10)
129: n -= 7;
130: if (OFFC < 12 && OFFO > 12)
131: n -= 7;
132: if (OFFO < 8 && OFFC > 8)
133: n += 7;
134: if (OFFO < 10 && OFFC > 10)
135: n += 7;
136: if (OFFO < 12 && OFFC > 12)
137: n += 7;
138: n += ((OFFC-OFFO)*7)/2;
139: }
140:
141: #ifdef DEBUG
142: fprintf (trace,"off = %d, ",n);
143: #endif
144:
145: /* see if men are trapped */
146: n -= freemen(bar);
147: n += freemen(home);
148: n += trapped(home,-cturn);
149: n -= trapped(bar,cturn);
150:
151: #ifdef DEBUG
152: fprintf (trace,"free = %d\n",n);
153: fprintf (trace,"\tOFFC = %d, OFFO = %d\n",OFFC,OFFO);
154: fflush (trace);
155: #endif
156:
157: /* double if 2-3 moves ahead */
158: if (n > 10+rnum(7))
159: return(1);
160: return (0);
161: }
162:
163: freemen (b)
164: int b;
165:
166: {
167: register int i, inc, lim;
168:
169: odds(0,0,0);
170: if (board[b] == 0)
171: return (0);
172: inc = (b == 0? 1: -1);
173: lim = (b == 0? 7: 18);
174: for (i = b+inc; i != lim; i += inc)
175: if (board[i]*inc < -1)
176: odds(abs(b-i),0,abs(board[b]));
177: if (abs(board[b]) == 1)
178: return ((36-count())/5);
179: return (count()/5);
180: }
181:
182: trapped (n,inc)
183: int n, inc;
184:
185: {
186: register int i, j, k;
187: int c, l, ct;
188:
189: ct = 0;
190: l = n+7*inc;
191: for (i = n+inc; i != l; i += inc) {
192: odds (0,0,0);
193: c = abs(i-l);
194: if (board[i]*inc > 0) {
195: for (j = c; j < 13; j++)
196: if (board[i+inc*j]*inc < -1) {
197: if (j < 7)
198: odds (j,0,1);
199: for (k = 1; k < 7 && k < j; k++)
200: if (j-k < 7)
201: odds (k,j-k,1);
202: }
203: ct += abs(board[i])*(36-count());
204: }
205: }
206: return (ct/5);
207: }
208:
209: eval () {
210:
211: register int i, j;
212:
213: for (j = i = 0; i < 26; i++)
214: j += (board[i] >= 0 ? i*board[i] : (25-i)*board[i]);
215:
216: if (off[1] >= 0)
217: j += 25*off[1];
218: else
219: j += 25*(off[1]+15);
220:
221: if (off[0] >= 0)
222: j -= 25*off[0];
223: else
224: j -= 25*(off[0]+15);
225: return (j);
226: }
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