300 lines
6.8 KiB
C
Executable file
300 lines
6.8 KiB
C
Executable file
/* tic tac toe (noughts and crosses) Author: Warren Toomey */
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/* Copyright 1988 by Warren Toomey wkt@cs.adfa.oz.au[@uunet.uu.net]
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*
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* You may freely copy or distribute this code as long as this notice
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* remains intact.
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*
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* You may modify this code, as long as this notice remains intact, and
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* you add another notice indicating that the code has been modified.
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*
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* You may NOT sell this code or in any way profit from this code without
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* prior agreement from the author.
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*/
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/* Compile with cc -o tic tic.c -lcurses -ltermcap */
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#include <stdlib.h>
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#include <time.h>
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#ifdef CURSES
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#include <curses.h>
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#endif
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#include <stdio.h>
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#ifndef CURSES
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#define printw printf
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#endif
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typedef struct {
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int value; /* The move returned by the */
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int path; /* alphabeta consists of a value */
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} MOVE; /* and an actual move (path) */
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_PROTOTYPE(int main, (void));
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_PROTOTYPE(int stateval, (int board [], int whosemove));
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_PROTOTYPE(MOVE alphabeta, (int board [], int whosemove, int alpha, int beta));
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_PROTOTYPE(void draw, (int board []));
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_PROTOTYPE(void getmove, (int board []));
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_PROTOTYPE(int endofgame, (int board []));
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_PROTOTYPE(int randommove, (void));
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/* Static evaluator. Returns 100 if we have 3 in a row -100 if they have 3
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* in a row
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*
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* Board is array of 9 ints, where 0=empty square 1=our move 4= their move
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*
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* and board is indices 0 1 2 3 4 5 6 7 8 */
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int stateval(board, whosemove)
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int board[];
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int whosemove;
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{
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static int row[8][3] = {{0, 1, 2}, {3, 4, 5}, {6, 7, 8}, /* Indices of 3in-a-rows */
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{0, 3, 6}, {1, 4, 7}, {2, 5, 8},
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{0, 4, 8}, {2, 4, 6}};
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int temp; /* Temp row results */
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int i, j; /* Loop counters */
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int side; /* Depth multiplier */
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int win, lose;
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if (whosemove == 1) {
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win = 100;
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lose = -100;
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side = 1;
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} else {
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/* Multiply by -1 if */
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win = -100;
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lose = 100;
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side = -1;
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} /* not out move */
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for (i = 0; i < 8; i++) { /* For every 3-in-a-row */
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temp = 0;
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for (j = 0; j < 3; j++) /* Add up the board values */
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temp += board[row[i][j]];
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if (temp == 3) return(win); /* We've got 3 in a row */
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if (temp == 12) return (lose); /* They've got 3 in a row */
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}
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return(0); /* Finally return sum */
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}
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MOVE alphabeta(board, whosemove, alpha, beta) /* Alphabeta: takes a board, */
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int board[]; /* whose move, alpha & beta cutoffs, */
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int whosemove; /* and returns a move to make and */
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int alpha; /* the value that the move has */
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int beta;
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{
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MOVE result, successor;
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int best_score, i, best_path, mademove;
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result.value = stateval(board, whosemove); /* Work out the board's */
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/* Static value */
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if ((result.value == 100) || /* If a win or loss already */
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(result.value == -100))
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return(result); /* return the result */
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best_score = beta; /* Ok, set worst score */
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mademove = 0; /* to the beta cutoff */
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for (i = 0; i < 9; i++) {
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if (board[i] == 0) { /* For all valid moves */
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mademove = 1;
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board[i] = whosemove; /* make the move on board */
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successor = alphabeta(board, 5 - whosemove, -best_score - 1, -alpha - 1);
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/* Get value of the move */
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board[i] = 0; /* Take move back */
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if (-successor.value > best_score) { /* If a better score */
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best_score = -successor.value; /* update our score */
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best_path = i; /* and move */
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if (best_score > alpha)
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break; /* If we've beaten alpha */
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} /* return immediately */
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}
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}
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if (mademove) {
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result.value = best_score; /* Finally return best score */
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result.path = best_path;/* and best move */
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}
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return(result); /* If no move, return static result */
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}
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void draw(board) /* Draw the board */
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int board[];
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{
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int i, j, row;
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static char out[] = " X O"; /* Lookup table for character */
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row = 6;
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#ifdef CURSES
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move(row, 0);
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#endif
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for (j = 0; j < 9; j += 3) {
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printw(" %d | %d | %d ", j, j + 1, j + 2);
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for (i = 0; i < 3; i++) {
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printw("%c ", out[board[j + i]]);
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if (i < 2) printw("| ");
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}
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if (j < 4) {
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#ifdef CURSES
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move(++row, 0);
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#else
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printw("\n");
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#endif
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printw("---+---+--- ---+---+---");
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}
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#ifdef CURSES
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move(++row, 0);
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#else
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printw("\n");
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#endif
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}
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#ifdef CURSES
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refresh();
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#else
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printw("\n");
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#endif
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}
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void getmove(board) /* Get a player's move */
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int board[];
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{
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int Move;
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int ItemsRead;
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char dumc;
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do {
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do {
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#ifdef CURSES
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move(9, 40);
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printw("Your move: "); /* Prompt for move */
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refresh();
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#else
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printw("Your move: "); /* Prompt for move */
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#endif
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ItemsRead = scanf("%d", &Move); /* Input the move */
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if (ItemsRead == 0) scanf("%c", &dumc); /* Remove the offending character */
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}
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while (ItemsRead != 1);
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}
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while (board[Move]);
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board[Move] = 4; /* If legal, add to board */
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draw(board); /* Draw the board */
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}
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int endofgame(board) /* Determine end of the game */
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int board[];
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{
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int eval;
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int count;
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eval = stateval(board, 1);
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#ifdef CURSES
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move(20, 25);
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#endif
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if (eval == 100) {
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printw("I have beaten you.\n");
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return(1);
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}
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if (eval == -100) {
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printw("Bus error (core dumped)\n");
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return(1);
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}
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count = 0;
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for (eval = 0; eval < 9; eval++)
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if (board[eval] != 0) count++;
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if (count == 9) {
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printw("A draw!\n");
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return(1);
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}
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#ifdef CURSES
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refresh();
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#endif
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return(0);
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}
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int randommove()
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{ /* Make an initial random move */
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int i;
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i = abs((int) time((long *) 0));
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return(i % 9);
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}
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int main()
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{ /* The actual game */
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int i, board[9];
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char ch;
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MOVE ourmove;
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for (i = 0; i < 9; i++) board[i] = 0; /* Initialise the board */
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#ifdef CURSES
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initscr();
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clear();
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refresh();
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#endif
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printw(" TIC TAC TOE \n\n");
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printw(" Your moves are 'O'\n");
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printw(" My moves are 'X'\n\n");
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#ifdef CURSES
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move(5, 0);
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printw("Do you wish to move first: ");
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refresh();
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while (scanf("%c", &ch) != 1);
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move(5, 0);
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printw(" ......."); /* Kludge to get rid */
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refresh();
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move(5, 0);
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printw(" "); /* of input letter */
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refresh();
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#else
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do
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printw("Do you wish to move first: ");
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while (scanf("%c", &ch) != 1);
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#endif
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if ((ch != 'y') && (ch != 'Y')) {
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i = randommove(); /* If we move first */
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board[i] = 1; /* make it random */
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#ifdef CURSES
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move(7, 42);
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printw("My move: %d\n", i);
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refresh();
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#else
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printw("My move: %d\n", i);
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#endif
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}
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draw(board);
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getmove(board);
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while (1) {
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ourmove = alphabeta(board, 1, 99, -99); /* Get a move for us;
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* return wins */
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/* Immediately & ignore losses */
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board[ourmove.path] = 1;/* and make it */
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#ifdef CURSES
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move(7, 42);
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printw("My move: %d\n", ourmove.path);
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refresh();
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#else
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printw("My move: %d\n", ourmove.path);
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#endif
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draw(board);
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if (endofgame(board)) break; /* If end of game, exit */
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getmove(board); /* Get opponent's move */
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if (endofgame(board)) break; /* If end of game, exit */
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}
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#ifdef CURSES
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endwin();
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#endif
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return(0);
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}
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