X-Git-Url: https://ncurses.scripts.mit.edu/?p=ncurses.git;a=blobdiff_plain;f=test%2Fknight.c;h=dc04944acd73a593213d977d2aa995a71f2dc67c;hp=e759d42689af65104062458c34ac17efe762e3dd;hb=02f1dee48fe8af6ce054388fba739aa4f975004e;hpb=c633e5103a29a38532cf1925257b91cea33fd090

diff --git a/test/knight.c b/test/knight.c
index e759d426..dc04944a 100644
--- a/test/knight.c
+++ b/test/knight.c
@@ -1,3 +1,30 @@
+/****************************************************************************
+ * Copyright (c) 1998-2018,2019 Free Software Foundation, Inc.              *
+ *                                                                          *
+ * Permission is hereby granted, free of charge, to any person obtaining a  *
+ * copy of this software and associated documentation files (the            *
+ * "Software"), to deal in the Software without restriction, including      *
+ * without limitation the rights to use, copy, modify, merge, publish,      *
+ * distribute, distribute with modifications, sublicense, and/or sell       *
+ * copies of the Software, and to permit persons to whom the Software is    *
+ * furnished to do so, subject to the following conditions:                 *
+ *                                                                          *
+ * The above copyright notice and this permission notice shall be included  *
+ * in all copies or substantial portions of the Software.                   *
+ *                                                                          *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
+ * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
+ * THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
+ *                                                                          *
+ * Except as contained in this notice, the name(s) of the above copyright   *
+ * holders shall not be used in advertising or otherwise to promote the     *
+ * sale, use or other dealings in this Software without prior written       *
+ * authorization.                                                           *
+ ****************************************************************************/
 /*
  * Knight's Tour - a brain game
  *
@@ -6,88 +33,95 @@
  * Eric S. Raymond <esr@snark.thyrsus.com> July 22 1995.  Mouse support
  * added September 20th 1995.
  *
- * $Id: knight.c,v 1.18 2000/10/15 18:36:34 Brian.Raiter Exp $
+ * $Id: knight.c,v 1.46 2019/08/24 22:40:52 tom Exp $
  */
 
 #include <test.priv.h>
 
-#include <ctype.h>
-#include <signal.h>
-#include <string.h>
-
 /* board size */
-#define BDEPTH	8
-#define BWIDTH	8
+#define YLIMIT		8
+#define XLIMIT		8
+#define MAXMOVES	(ylimit * xlimit)
 
 /* where to start the instructions */
-#define INSTRY	2
-#define INSTRX	35
+#define INSTRY		2
+#define INSTRX		35
 
 /* corner of board */
-#define BOARDY	2
-#define BOARDX	0
+#define BOARDY		2
+#define BOARDX		0
 
 /* notification line */
-#define NOTIFYY	21
+#define NOTIFYY		21
 
 /* virtual color values */
 #define TRAIL_COLOR	1
 #define PLUS_COLOR	2
 #define MINUS_COLOR	3
 
-#define CX(x)	(2 + 4 * (x))
-#define CY(y)	(1 + 2 * (y))
+#define CX(x)		(2 + 4 * (x))
+#define CY(y)		(1 + 2 * (y))
 #define cellmove(y, x)	wmove(boardwin, CY(y), CX(x))
 #define CXINV(x)	(((x) - 1) / 4)
 #define CYINV(y)	(((y) - 2) / 2)
 
 typedef struct {
-    short x, y;
-} cell;
-
-static short board[BDEPTH][BWIDTH];	/* the squares */
-static int rw, col;		/* current row and column */
-static int lastrow, lastcol;	/* last location visited */
-static cell history[BDEPTH * BWIDTH + 1];	/* choice history */
-static int movecount;		/* count of moves so far */
+    int x, y;
+} HISTORY;
+
+typedef int SQUARES[YLIMIT][XLIMIT];
+
 static WINDOW *boardwin;	/* the board window */
 static WINDOW *helpwin;		/* the help window */
 static WINDOW *msgwin;		/* the message window */
-static chtype trail = '#';	/* trail character */
-static chtype plus = '+';	/* cursor hot-spot character */
-static chtype minus = '-';	/* possible-move character */
-static chtype oldch;
 
-static void init(void);
-static void play(void);
-static void dosquares(void);
-static void drawmove(char, int, int, int, int);
-static bool evalmove(int, int);
-static bool chkmoves(void);
-static bool chksqr(int, int);
-static int iabs(int);
-
-int
-main(int argc GCC_UNUSED, char *argv[]GCC_UNUSED)
-{
-    init();
+#if HAVE_USE_DEFAULT_COLORS
+static bool d_option;
+#endif
 
-    play();
+static chtype minus = '-';	/* possible-move character */
+static chtype oldch;
+static chtype plus = '+';	/* cursor hot-spot character */
+static chtype trail = '#';	/* trail character */
 
-    endwin();
-    return EXIT_SUCCESS;
-}
+static int ylimit = YLIMIT;
+static int xlimit = XLIMIT;
+static int maxmoves = (YLIMIT * XLIMIT);
+
+static int count_tries;		/* count of trials so far */
+static int test_test;		/* FIXME */
+/* *INDENT-OFF* */
+static const struct {
+    int y;
+    int x;
+} offsets[] = {
+    {  2,  1 },
+    {  1,  2 },
+    { -1,  2 },
+    { -2,  1 },
+    { -2, -1 },
+    { -1, -2 },
+    {  1, -2 },
+    {  2, -1 },
+};
+#define MAX_OFFSET	(unsigned)SIZEOF(offsets)
+/* *INDENT-ON* */
 
 static void
-init(void)
+init_program(void)
 {
+    setlocale(LC_ALL, "");
+
     srand((unsigned) getpid());
     initscr();
     cbreak();			/* immediate char return */
     noecho();			/* no immediate echo */
-    boardwin = newwin(BDEPTH * 2 + 1, BWIDTH * 4 + 1, BOARDY, BOARDX);
+
+    maxmoves = MAXMOVES;
+    boardwin = newwin(ylimit * 2 + 1, xlimit * 4 + 1, BOARDY, BOARDX);
     helpwin = newwin(0, 0, INSTRY, INSTRX);
     msgwin = newwin(1, INSTRX - 1, NOTIFYY, 0);
+
     scrollok(msgwin, TRUE);
     keypad(boardwin, TRUE);
 
@@ -96,21 +130,24 @@ init(void)
 
 	start_color();
 #if HAVE_USE_DEFAULT_COLORS
-	if (use_default_colors() == OK)
+	if (d_option && (use_default_colors() == OK))
 	    bg = -1;
 #endif
 
-	(void) init_pair(TRAIL_COLOR, COLOR_CYAN, bg);
-	(void) init_pair(PLUS_COLOR, COLOR_RED, bg);
-	(void) init_pair(MINUS_COLOR, COLOR_GREEN, bg);
+	(void) init_pair(TRAIL_COLOR, (short) COLOR_CYAN, (short) bg);
+	(void) init_pair(PLUS_COLOR, (short) COLOR_RED, (short) bg);
+	(void) init_pair(MINUS_COLOR, (short) COLOR_GREEN, (short) bg);
 
-	trail |= COLOR_PAIR(TRAIL_COLOR);
-	plus |= COLOR_PAIR(PLUS_COLOR);
-	minus |= COLOR_PAIR(MINUS_COLOR);
+	trail |= (chtype) COLOR_PAIR(TRAIL_COLOR);
+	plus |= (chtype) COLOR_PAIR(PLUS_COLOR);
+	minus |= (chtype) COLOR_PAIR(MINUS_COLOR);
     }
 #ifdef NCURSES_MOUSE_VERSION
     (void) mousemask(BUTTON1_CLICKED, (mmask_t *) NULL);
 #endif /* NCURSES_MOUSE_VERSION */
+#if defined(PDCURSES)
+    mouse_set(BUTTON1_RELEASED);
+#endif
 
     oldch = minus;
 }
@@ -136,8 +173,8 @@ help1(void)
     (void) waddstr(helpwin, "puzzle; also inform you when you run out\n");
     (void) waddstr(helpwin, "of legal moves.\n\n");
 
-    (void) mvwaddstr(helpwin, NOTIFYY - INSTRY, 0,
-		     "Press `?' to go to keystroke help.");
+    MvWAddStr(helpwin, NOTIFYY - INSTRY, 0,
+	      "Press `?' to go to keystroke help.");
 }
 
 static void
@@ -155,15 +192,400 @@ help2(void)
     (void) waddstr(helpwin, "x,q -- exit             y k u    7 8 9\n");
     (void) waddstr(helpwin, "r -- redraw screen       \\|/      \\|/ \n");
     (void) waddstr(helpwin, "bksp -- undo move       h-+-l    4-+-6\n");
-    (void) waddstr(helpwin, "                         /|\\      /|\\ \n");
-    (void) waddstr(helpwin, "                        b j n    1 2 3\n");
+    (void) waddstr(helpwin, "a -- autojump            /|\\      /|\\ \n");
+    if (ylimit <= 6) {
+	(void) waddstr(helpwin, "R -- solve (slow)       b j n    1 2 3\n");
+    } else {
+	(void) waddstr(helpwin, "                        b j n    1 2 3\n");
+    }
 
     (void) waddstr(helpwin, "\nYou can place your knight on the selected\n");
     (void) waddstr(helpwin, "square with spacebar, Enter, or the keypad\n");
-    (void) waddstr(helpwin, "center key.  You can quit with `x' or `q'.\n");
+    (void) waddstr(helpwin, "center key.  Use F/B to review the path.\n");
+
+    MvWAddStr(helpwin, NOTIFYY - INSTRY, 0,
+	      "Press `?' to go to game explanation");
+}
+
+static void
+show_help(bool * keyhelp)
+{
+    werase(helpwin);
+    if (*keyhelp) {
+	help1();
+	*keyhelp = FALSE;
+    } else {
+	help2();
+	*keyhelp = TRUE;
+    }
+    wrefresh(helpwin);
+}
+
+static inline bool
+isValidYX(int y, int x)
+{
+    return (y >= 0 && y < ylimit && x >= 0 && x < xlimit) ? TRUE : FALSE;
+}
+
+static inline bool
+isUnusedYX(SQUARES squares, int y, int x)
+{
+    return (isValidYX(y, x) && (!squares[y][x]) ? TRUE : FALSE);
+}
+
+static bool
+boardIsFilled(SQUARES squares, int y, int x)
+{
+    unsigned n;
+
+    for (n = 0; n < MAX_OFFSET; n++) {
+	if (isUnusedYX(squares, y + offsets[n].y, x + offsets[n].x)) {
+	    return FALSE;
+	}
+    }
+    return TRUE;
+}
+
+static void
+drawBoard(void)
+{
+    int i, j;
+
+    MvAddStr(0, 20, "KNIGHT'S MOVE -- a logical solitaire");
+
+    move(BOARDY, BOARDX);
+    waddch(boardwin, ACS_ULCORNER);
+    for (j = 0; j < (ylimit - 1); j++) {
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_TTEE);
+    }
+    waddch(boardwin, ACS_HLINE);
+    waddch(boardwin, ACS_HLINE);
+    waddch(boardwin, ACS_HLINE);
+    waddch(boardwin, ACS_URCORNER);
+
+    for (i = 1; i < ylimit; i++) {
+	move(BOARDY + i * 2 - 1, BOARDX);
+	waddch(boardwin, ACS_VLINE);
+	for (j = 0; j < xlimit; j++) {
+	    waddch(boardwin, ' ');
+	    waddch(boardwin, ' ');
+	    waddch(boardwin, ' ');
+	    waddch(boardwin, ACS_VLINE);
+	}
+	move(BOARDY + i * 2, BOARDX);
+	waddch(boardwin, ACS_LTEE);
+	for (j = 0; j < xlimit - 1; j++) {
+	    waddch(boardwin, ACS_HLINE);
+	    waddch(boardwin, ACS_HLINE);
+	    waddch(boardwin, ACS_HLINE);
+	    waddch(boardwin, ACS_PLUS);
+	}
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_RTEE);
+    }
+
+    move(BOARDY + i * 2 - 1, BOARDX);
+    waddch(boardwin, ACS_VLINE);
+    for (j = 0; j < xlimit; j++) {
+	waddch(boardwin, ' ');
+	waddch(boardwin, ' ');
+	waddch(boardwin, ' ');
+	waddch(boardwin, ACS_VLINE);
+    }
+
+    move(BOARDY + i * 2, BOARDX);
+    waddch(boardwin, ACS_LLCORNER);
+    for (j = 0; j < xlimit - 1; j++) {
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_HLINE);
+	waddch(boardwin, ACS_BTEE);
+    }
+    waddch(boardwin, ACS_HLINE);
+    waddch(boardwin, ACS_HLINE);
+    waddch(boardwin, ACS_HLINE);
+    waddch(boardwin, ACS_LRCORNER);
+}
+
+static void
+mark_possibles(SQUARES squares, int y, int x, chtype mark)
+{
+    unsigned n;
+
+    for (n = 0; n < MAX_OFFSET; n++) {
+	if (isUnusedYX(squares, y + offsets[n].y, x + offsets[n].x)) {
+	    cellmove(y + offsets[n].y, x + offsets[n].x);
+	    waddch(boardwin, mark);
+	}
+    }
+}
+
+static bool
+find_next_move(SQUARES squares, HISTORY * doneData, int doneSize, int *y, int *x)
+{
+    bool result = FALSE;
+
+    if (doneSize > 1) {
+	unsigned j;
+	int oldy = doneData[doneSize - 1].y;
+	int oldx = doneData[doneSize - 1].x;
+	int found = -1;
+	int first = -1;
+	int next = -1;
+
+	for (j = 0; j < MAX_OFFSET * 2; j++) {
+	    unsigned k = j % MAX_OFFSET;
+	    int newy = oldy + offsets[k].y;
+	    int newx = oldx + offsets[k].x;
+	    if (isUnusedYX(squares, newy, newx)) {
+		if (first < 0)
+		    first = (int) k;
+		if (newy == *y
+		    && newx == *x) {
+		    found = (int) k;
+		} else if (found >= 0) {
+		    next = (int) k;
+		    break;
+		}
+	    }
+	}
+	if (found < 0)
+	    next = first;
+	if (next >= 0) {
+	    *y = oldy + offsets[next].y;
+	    *x = oldx + offsets[next].x;
+	}
+	result = TRUE;
+    }
+    return result;
+}
+
+static void
+count_next_moves(SQUARES squares, int count_moves, int y, int x)
+{
+    int count = 0;
+    unsigned j;
+
+    wprintw(msgwin, "\nMove %d", count_moves);
+    for (j = 0; j < MAX_OFFSET; j++) {
+	int newy = y + offsets[j].y;
+	int newx = x + offsets[j].x;
+	if (isUnusedYX(squares, newy, newx)) {
+	    ++count;
+	}
+    }
+    wprintw(msgwin, ", gives %d choices", count);
+    wclrtoeol(msgwin);
+}
+
+static void
+unmarkcell(int row, int column)
+{
+    cellmove(row, column);
+    waddch(boardwin, '\b');
+    waddch(boardwin, ' ');
+    waddch(boardwin, minus);
+    waddch(boardwin, ' ');
+}
+
+static void
+markcell(chtype tchar, int row, int column)
+{
+    cellmove(row, column);
+    waddch(boardwin, '\b');
+    waddch(boardwin, tchar);
+    waddch(boardwin, tchar);
+    waddch(boardwin, tchar);
+}
+
+static void
+drawMove(SQUARES squares, int count_moves, chtype tchar, int oldy, int oldx, int
+	 row, int column)
+/* place the stars, update board & currents */
+{
+    if (count_moves <= 1) {
+	int i, j;
+
+	for (i = 0; i < ylimit; i++) {
+	    for (j = 0; j < xlimit; j++) {
+		if (count_moves == 0) {
+		    unmarkcell(i, j);
+		} else {
+		    cellmove(i, j);
+		    if (winch(boardwin) == minus)
+			waddch(boardwin, ' ');
+		}
+	    }
+	}
+    } else {
+	markcell(tchar, oldy, oldx);
+	mark_possibles(squares, oldy, oldx, ' ');
+    }
+
+    if (row >= 0 && column >= 0) {
+	markcell(trail, row, column);
+	mark_possibles(squares, row, column, minus);
+	squares[row][column] = TRUE;
+    }
+
+    wprintw(msgwin, "\nMove %d", count_moves);
+    if (count_tries != count_moves)
+	wprintw(msgwin, " (%d tries)", count_tries);
+    wclrtoeol(msgwin);
+}
+
+static int
+iabs(int num)
+{
+    if (num < 0)
+	return (-num);
+    else
+	return (num);
+}
+
+static bool
+evaluate_move(SQUARES squares, HISTORY * doneData, int doneSize, int row, int column)
+{
+    if (doneSize <= 1)
+	return (TRUE);
+    else if (squares[row][column] == TRUE) {
+	waddstr(msgwin, "\nYou've already been there.");
+	return (FALSE);
+    } else {
+	int rdif = iabs(row - doneData[doneSize - 1].y);
+	int cdif = iabs(column - doneData[doneSize - 1].x);
+
+	if (!((rdif == 1) && (cdif == 2)) && !((rdif == 2) && (cdif == 1))) {
+	    waddstr(msgwin, "\nThat's not a legal knight's move.");
+	    return (FALSE);
+	}
+    }
+
+    return (TRUE);
+}
+
+static int
+completed(SQUARES squares)
+{
+    int i, j, count = 0;
+
+    for (i = 0; i < ylimit; i++) {
+	for (j = 0; j < xlimit; j++) {
+	    if (squares[i][j] != 0) {
+		count += 1;
+	    }
+	}
+    }
+    return ((count == maxmoves) ? -1 : count);
+}
+
+static void
+no_previous_move(void)
+{
+    waddstr(msgwin, "\nNo previous move.");
+    beep();
+}
+
+/* Recursively try all possible moves, starting from (y,x) */
+static int
+recurBack(SQUARES squares, int y, int x, int total)
+{
+    int longest = total;
+    int best_x = x;
+    int best_y = y;
+    int result;
+
+    if (total < maxmoves) {
+	unsigned k;
+
+	for (k = 0; k < MAX_OFFSET; k++) {
+	    int try_x = x + offsets[k].x;
+	    int try_y = y + offsets[k].y;
+	    if (isUnusedYX(squares, try_y, try_x)) {
+		++test_test;
+		squares[try_y][try_x] = total + 1;
+		result = recurBack(squares, try_y, try_x, total + 1);
+		if (result > longest) {
+		    longest = result;
+		    best_x = try_x;
+		    best_y = try_y;
+		}
+		if (result >= maxmoves)
+		    break;
+		squares[try_y][try_x] = 0;	/* allow retry... */
+	    }
+	}
+    }
+
+    result = total;
+    if (longest > total) {
+	result = longest;
+	squares[best_y][best_x] = total + 1;
+	(void) recurBack(squares, best_y, best_x, total + 1);
+	if (result < maxmoves)
+	    squares[best_y][best_x] = 0;
+    }
+
+    return result;
+}
 
-    (void) mvwaddstr(helpwin, NOTIFYY - INSTRY, 0,
-		     "Press `?' to go to game explanation");
+/*
+ * Solve the Knight Tour problem using backtracking, returning the length of
+ * the resulting solution.  If this is invoked from a point where the remaining
+ * choices cannot complete the tour, the result will fall short.
+ */
+static int
+useBacktracking(SQUARES result, HISTORY * doneData, int doneSize)
+{
+    int y = 0, x = 0, n;
+    SQUARES squares;
+    int total;
+    int actual = doneSize - 1;
+
+    memset(squares, 0, sizeof(squares));
+    for (n = 1; n <= actual; ++n) {
+	y = doneData[n].y;
+	x = doneData[n].x;
+	squares[y][x] = n;
+    }
+
+    total = recurBack(squares, y, x, actual);
+    if (total > actual) {
+	for (y = 0; y < ylimit; ++y) {
+	    for (x = 0; x < xlimit; ++x) {
+		result[y][x] = squares[y][x];
+		if ((n = squares[y][x]) != 0) {
+		    doneData[n].y = y;
+		    doneData[n].x = x;
+		}
+	    }
+	}
+    }
+    return total;
+}
+
+static int
+reviewHistory(HISTORY * history, int count_moves, int review, int *ny, int *nx)
+{
+    if (review < 0) {
+	beep();
+	review = 0;
+    } else if (review > count_moves - 2) {
+	beep();
+	review = count_moves - 2;
+    } else {
+	*ny = history[count_moves - review - 1].y;
+	*nx = history[count_moves - review - 1].x;
+	wprintw(msgwin, "\nReview %d:%d.", count_moves - review - 1,
+		count_moves - 1);
+	wrefresh(msgwin);
+    }
+    return review;
 }
 
 static void
@@ -171,15 +593,24 @@ play(void)
 /* play the game */
 {
     bool keyhelp;		/* TRUE if keystroke help is up */
-    int c, ny = 0, nx = 0;
     int i, j, count;
+    int lastcol = 0;		/* last location visited */
+    int lastrow = 0;
+    int ny = 0, nx = 0;
+    int review = 0;		/* review history */
+    int test_size;
+    int rw = 0, col = 0;	/* current row and column */
 
     do {
+	SQUARES squares;
+	HISTORY history[(YLIMIT * XLIMIT) + 1];
+	int count_moves = 0;	/* count of moves so far */
+
 	/* clear screen and draw board */
 	werase(boardwin);
 	werase(helpwin);
 	werase(msgwin);
-	dosquares();
+	drawBoard();
 	help1();
 	wnoutrefresh(stdscr);
 	wnoutrefresh(helpwin);
@@ -187,23 +618,26 @@ play(void)
 	wnoutrefresh(boardwin);
 	doupdate();
 
-	for (i = 0; i < BDEPTH; i++)
-	    for (j = 0; j < BWIDTH; j++) {
-		board[i][j] = FALSE;
-		cellmove(i, j);
-		waddch(boardwin, minus);
+	for (i = 0; i < ylimit; i++) {
+	    for (j = 0; j < xlimit; j++) {
+		squares[i][j] = FALSE;
+		unmarkcell(i, j);
 	    }
-	memset(history, '\0', sizeof(history));
+	}
+	memset(history, 0, sizeof(history));
 	history[0].y = history[0].x = -1;
+	history[1].y = history[1].x = -1;
 	lastrow = lastcol = -2;
-	movecount = 1;
+	count_moves = 1;
+	count_tries = 1;
 	keyhelp = FALSE;
+	show_help(&keyhelp);
 
 	for (;;) {
 	    if (rw != lastrow || col != lastcol) {
 		if (lastrow >= 0 && lastcol >= 0) {
 		    cellmove(lastrow, lastcol);
-		    if (board[lastrow][lastcol])
+		    if (squares[lastrow][lastcol])
 			waddch(boardwin, trail);
 		    else
 			waddch(boardwin, oldch);
@@ -221,15 +655,11 @@ play(void)
 
 	    wrefresh(msgwin);
 
-	    c = wgetch(boardwin);
-
-	    werase(msgwin);
-
-	    switch (c) {
+	    switch (wgetch(boardwin)) {
 	    case 'k':
 	    case '8':
 	    case KEY_UP:
-		ny = rw + BDEPTH - 1;
+		ny = rw + ylimit - 1;
 		nx = col;
 		break;
 	    case 'j':
@@ -242,7 +672,7 @@ play(void)
 	    case '4':
 	    case KEY_LEFT:
 		ny = rw;
-		nx = col + BWIDTH - 1;
+		nx = col + xlimit - 1;
 		break;
 	    case 'l':
 	    case '6':
@@ -253,19 +683,19 @@ play(void)
 	    case 'y':
 	    case '7':
 	    case KEY_A1:
-		ny = rw + BDEPTH - 1;
-		nx = col + BWIDTH - 1;
+		ny = rw + ylimit - 1;
+		nx = col + xlimit - 1;
 		break;
 	    case 'b':
 	    case '1':
 	    case KEY_C1:
 		ny = rw + 1;
-		nx = col + BWIDTH - 1;
+		nx = col + xlimit - 1;
 		break;
 	    case 'u':
 	    case '9':
 	    case KEY_A3:
-		ny = rw + BDEPTH - 1;
+		ny = rw + ylimit - 1;
 		nx = col + 1;
 		break;
 	    case 'n':
@@ -275,14 +705,15 @@ play(void)
 		nx = col + 1;
 		break;
 
-#ifdef NCURSES_MOUSE_VERSION
+#ifdef KEY_MOUSE
 	    case KEY_MOUSE:
+#ifdef NCURSES_MOUSE_VERSION
 		{
 		    MEVENT myevent;
 
 		    getmouse(&myevent);
-		    if (myevent.y >= CY(0) && myevent.y <= CY(BDEPTH)
-			&& myevent.x >= CX(0) && myevent.x <= CX(BWIDTH)) {
+		    if (myevent.y >= CY(0) && myevent.y <= CY(ylimit)
+			&& myevent.x >= CX(0) && myevent.x <= CX(xlimit)) {
 			nx = CXINV(myevent.x);
 			ny = CYINV(myevent.y);
 			ungetch('\n');
@@ -293,53 +724,92 @@ play(void)
 		    }
 		}
 #endif /* NCURSES_MOUSE_VERSION */
+#ifdef PDCURSES
+		{
+		    int test_y, test_x;
+		    request_mouse_pos();
+		    test_y = MOUSE_Y_POS + 0;
+		    test_x = MOUSE_X_POS + 1;
+		    if (test_y >= CY(0) && test_y <= CY(ylimit)
+			&& test_x >= CX(0) && test_x <= CX(xlimit)) {
+			ny = CYINV(test_y);
+			nx = CXINV(test_x);
+			wmove(helpwin, 0, 0);
+			wrefresh(helpwin);
+			ungetch('\n');
+		    }
+		    break;
+		}
+#endif /* PDCURSES */
+#endif /* KEY_MOUSE */
 
 	    case KEY_B2:
 	    case '\n':
 	    case ' ':
-		if (evalmove(rw, col)) {
-		    drawmove(trail,
-			     history[movecount - 1].y,
-			     history[movecount - 1].x,
+		review = 0;
+		if (evaluate_move(squares, history, count_moves, rw, col)) {
+		    drawMove(squares,
+			     count_moves,
+			     trail,
+			     history[count_moves - 1].y,
+			     history[count_moves - 1].x,
 			     rw, col);
-		    history[movecount].y = rw;
-		    history[movecount].x = col;
-		    movecount++;
-
-		    if (!chkmoves())
-			goto dropout;
-		} else
+		    history[count_moves].y = (short) rw;
+		    history[count_moves].x = (short) col;
+		    count_moves++;
+		    count_tries++;
+
+		    if (boardIsFilled(squares, rw, col)) {
+			if (completed(squares) < 0) {
+			    waddstr(msgwin, "\nYou won.");
+			} else {
+			    waddstr(msgwin,
+				    "\nNo further moves are possible.");
+			}
+		    }
+		} else {
 		    beep();
-		break;
-
-	    case KEY_REDO:
-	    case '\f':
-	    case 'r':
-		clearok(curscr, TRUE);
-		wnoutrefresh(stdscr);
-		wnoutrefresh(boardwin);
-		wnoutrefresh(msgwin);
-		wnoutrefresh(helpwin);
-		doupdate();
+		}
 		break;
 
 	    case KEY_UNDO:
 	    case KEY_BACKSPACE:
 	    case '\b':
-		if (movecount == 1) {
-		    ny = lastrow;
-		    nx = lastcol;
-		    waddstr(msgwin, "\nNo previous move.");
-		    beep();
+		review = 0;
+		if (count_moves <= 0) {
+		    no_previous_move();
+		} else if (count_moves <= 1) {
+		    ny = history[count_moves].y;
+		    nx = history[count_moves].x;
+		    if (nx < 0 || ny < 0) {
+			ny = (lastrow >= 0) ? lastrow : 0;
+			nx = (lastcol >= 0) ? lastcol : 0;
+		    }
+		    count_moves = 0;
+		    squares[ny][nx] = FALSE;
+		    oldch = minus;
+		    drawMove(squares, count_moves, ' ', ny, nx, -1, -1);
+		    count_moves = 1;
+		    count_tries = 1;
+		    no_previous_move();
 		} else {
-		    int oldy = history[movecount - 1].y;
-		    int oldx = history[movecount - 1].x;
+		    int oldy = history[count_moves - 1].y;
+		    int oldx = history[count_moves - 1].x;
 
-		    board[oldy][oldx] = FALSE;
-		    --movecount;
-		    ny = history[movecount - 1].y;
-		    nx = history[movecount - 1].x;
-		    drawmove(' ', oldy, oldx, ny, nx);
+		    if (!squares[rw][col]) {
+			cellmove(rw, col);
+			waddch(boardwin, ' ');
+		    }
+
+		    squares[oldy][oldx] = FALSE;
+		    --count_moves;
+		    ny = history[count_moves - 1].y;
+		    nx = history[count_moves - 1].x;
+		    if (nx < 0 || ny < 0) {
+			ny = oldy;
+			nx = oldx;
+		    }
+		    drawMove(squares, count_moves, ' ', oldy, oldx, ny, nx);
 
 		    /* avoid problems if we just changed the current cell */
 		    cellmove(lastrow, lastcol);
@@ -347,20 +817,65 @@ play(void)
 		}
 		break;
 
+	    case 'a':
+		nx = col;
+		ny = rw;
+		if (find_next_move(squares, history, count_moves, &ny, &nx))
+		    count_next_moves(squares, count_moves, ny, nx);
+		else
+		    beep();
+		break;
+
+	    case 'F':
+		review = reviewHistory(history, count_moves, review - 1,
+				       &ny, &nx);
+		break;
+
+	    case 'B':
+		review = reviewHistory(history, count_moves, review + 1,
+				       &ny, &nx);
+		break;
+
+	    case 'R':
+		if (ylimit <= 6) {
+		    wprintw(msgwin, "\nworking...");
+		    wrefresh(msgwin);
+		    test_test = 0;
+		    test_size = useBacktracking(squares, history, count_moves);
+		    wprintw(msgwin, "\nOk %d:%d (%d tests)",
+			    test_size, maxmoves, test_test);
+		    review = 0;
+		    while (count_moves <= test_size) {
+			markcell(trail,
+				 ny = history[count_moves].y,
+				 nx = history[count_moves].x);
+			count_moves++;
+		    }
+		} else {
+		    wprintw(msgwin, "\nBoard is too large.");
+		}
+		wrefresh(msgwin);
+		break;
+
+#if HAVE_CURSCR
+	    case KEY_REDO:
+	    case '\f':
+	    case 'r':
+		clearok(curscr, TRUE);
+		wnoutrefresh(stdscr);
+		wnoutrefresh(boardwin);
+		wnoutrefresh(msgwin);
+		wnoutrefresh(helpwin);
+		doupdate();
+		break;
+#endif
+
 	    case 'q':
 	    case 'x':
 		goto dropout;
 
-	    case '?':
-		werase(helpwin);
-		if (keyhelp) {
-		    help1();
-		    keyhelp = FALSE;
-		} else {
-		    help2();
-		    keyhelp = TRUE;
-		}
-		wrefresh(helpwin);
+	    case HELP_KEY_1:
+		show_help(&keyhelp);
 		break;
 
 	    default:
@@ -368,224 +883,73 @@ play(void)
 		break;
 	    }
 
-	    col = nx % BWIDTH;
-	    rw = ny % BDEPTH;
+	    col = nx % xlimit;
+	    rw = ny % ylimit;
 	}
 
       dropout:
-	count = 0;
-	for (i = 0; i < BDEPTH; i++)
-	    for (j = 0; j < BWIDTH; j++)
-		if (board[i][j] != 0)
-		    count += 1;
-	if (count == (BWIDTH * BDEPTH))
+	if ((count = completed(squares)) < 0)
 	    wprintw(msgwin, "\nYou won.  Care to try again? ");
 	else
 	    wprintw(msgwin, "\n%d squares filled.  Try again? ", count);
+	wclrtoeol(msgwin);
     } while
 	(tolower(wgetch(msgwin)) == 'y');
 }
 
 static void
-dosquares(void)
-{
-    int i, j;
-
-    mvaddstr(0, 20, "KNIGHT'S MOVE -- a logical solitaire");
-
-    move(BOARDY, BOARDX);
-    waddch(boardwin, ACS_ULCORNER);
-    for (j = 0; j < 7; j++) {
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_TTEE);
-    }
-    waddch(boardwin, ACS_HLINE);
-    waddch(boardwin, ACS_HLINE);
-    waddch(boardwin, ACS_HLINE);
-    waddch(boardwin, ACS_URCORNER);
-
-    for (i = 1; i < BDEPTH; i++) {
-	move(BOARDY + i * 2 - 1, BOARDX);
-	waddch(boardwin, ACS_VLINE);
-	for (j = 0; j < BWIDTH; j++) {
-	    waddch(boardwin, ' ');
-	    waddch(boardwin, ' ');
-	    waddch(boardwin, ' ');
-	    waddch(boardwin, ACS_VLINE);
-	}
-	move(BOARDY + i * 2, BOARDX);
-	waddch(boardwin, ACS_LTEE);
-	for (j = 0; j < BWIDTH - 1; j++) {
-	    waddch(boardwin, ACS_HLINE);
-	    waddch(boardwin, ACS_HLINE);
-	    waddch(boardwin, ACS_HLINE);
-	    waddch(boardwin, ACS_PLUS);
-	}
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_RTEE);
-    }
-
-    move(BOARDY + i * 2 - 1, BOARDX);
-    waddch(boardwin, ACS_VLINE);
-    for (j = 0; j < BWIDTH; j++) {
-	waddch(boardwin, ' ');
-	waddch(boardwin, ' ');
-	waddch(boardwin, ' ');
-	waddch(boardwin, ACS_VLINE);
-    }
-
-    move(BOARDY + i * 2, BOARDX);
-    waddch(boardwin, ACS_LLCORNER);
-    for (j = 0; j < BWIDTH - 1; j++) {
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_HLINE);
-	waddch(boardwin, ACS_BTEE);
-    }
-    waddch(boardwin, ACS_HLINE);
-    waddch(boardwin, ACS_HLINE);
-    waddch(boardwin, ACS_HLINE);
-    waddch(boardwin, ACS_LRCORNER);
-}
-
-static void
-mark_possibles(int prow, int pcol, chtype mark)
+usage(void)
 {
-    if (chksqr(prow + 2, pcol + 1)) {
-	cellmove(prow + 2, pcol + 1);
-	waddch(boardwin, mark);
-    };
-    if (chksqr(prow + 2, pcol - 1)) {
-	cellmove(prow + 2, pcol - 1);
-	waddch(boardwin, mark);
-    };
-    if (chksqr(prow - 2, pcol + 1)) {
-	cellmove(prow - 2, pcol + 1);
-	waddch(boardwin, mark);
-    };
-    if (chksqr(prow - 2, pcol - 1)) {
-	cellmove(prow - 2, pcol - 1);
-	waddch(boardwin, mark);
-    };
-    if (chksqr(prow + 1, pcol + 2)) {
-	cellmove(prow + 1, pcol + 2);
-	waddch(boardwin, mark);
-    };
-    if (chksqr(prow + 1, pcol - 2)) {
-	cellmove(prow + 1, pcol - 2);
-	waddch(boardwin, mark);
-    };
-    if (chksqr(prow - 1, pcol + 2)) {
-	cellmove(prow - 1, pcol + 2);
-	waddch(boardwin, mark);
-    };
-    if (chksqr(prow - 1, pcol - 2)) {
-	cellmove(prow - 1, pcol - 2);
-	waddch(boardwin, mark);
+    static const char *msg[] =
+    {
+	"Usage: knight [options]"
+	,""
+	,"Options:"
+#if HAVE_USE_DEFAULT_COLORS
+	," -d       invoke use_default_colors"
+#endif
+	," -n NUM   set board-size to NUM*NUM (default 8x8)"
     };
-}
-
-static void
-drawmove(char tchar, int oldy, int oldx, int row, int column)
-/* place the stars, update board & currents */
-{
-    if (movecount <= 1) {
-	int i, j;
+    size_t n;
 
-	for (i = 0; i < BDEPTH; i++)
-	    for (j = 0; j < BWIDTH; j++) {
-		cellmove(i, j);
-		if (winch(boardwin) == minus)
-		    waddch(boardwin, movecount ? ' ' : minus);
-	    }
-    } else {
-	cellmove(oldy, oldx);
-	waddch(boardwin, '\b');
-	waddch(boardwin, tchar);
-	waddch(boardwin, tchar);
-	waddch(boardwin, tchar);
-	mark_possibles(oldy, oldx, ' ');
-    }
+    for (n = 0; n < SIZEOF(msg); n++)
+	fprintf(stderr, "%s\n", msg[n]);
 
-    if (row != -1 && column != -1) {
-	cellmove(row, column);
-	waddch(boardwin, '\b');
-	waddch(boardwin, trail);
-	waddch(boardwin, trail);
-	waddch(boardwin, trail);
-	mark_possibles(row, column, minus);
-	board[row][column] = TRUE;
-    }
-
-    wprintw(msgwin, "\nMove %d", movecount);
+    ExitProgram(EXIT_FAILURE);
 }
 
-static bool
-evalmove(int row, int column)
-/* evaluate move */
+int
+main(int argc, char *argv[])
 {
-    if (movecount == 1)
-	return (TRUE);
-    else if (board[row][column] == TRUE) {
-	waddstr(msgwin, "\nYou've already been there.");
-	return (FALSE);
-    } else {
-	int rdif = iabs(row - history[movecount - 1].y);
-	int cdif = iabs(column - history[movecount - 1].x);
+    int ch;
 
-	if (!((rdif == 1) && (cdif == 2)) && !((rdif == 2) && (cdif == 1))) {
-	    waddstr(msgwin, "\nThat's not a legal knight's move.");
-	    return (FALSE);
+    while ((ch = getopt(argc, argv, "dn:")) != -1) {
+	switch (ch) {
+#if HAVE_USE_DEFAULT_COLORS
+	case 'd':
+	    d_option = TRUE;
+	    break;
+#endif
+	case 'n':
+	    ch = atoi(optarg);
+	    if (ch < 3 || ch > 8) {
+		fprintf(stderr, "board size %d is outside [3..8]\n", ch);
+		usage();
+	    }
+	    xlimit = ylimit = ch;
+	    break;
+	default:
+	    usage();
+	    /* NOTREACHED */
 	}
     }
+    if (optind < argc)
+	usage();
 
-    return (TRUE);
-}
+    init_program();
 
-static bool
-chkmoves(void)
-/* check to see if valid moves are available */
-{
-    if (chksqr(rw + 2, col + 1))
-	return (TRUE);
-    if (chksqr(rw + 2, col - 1))
-	return (TRUE);
-    if (chksqr(rw - 2, col + 1))
-	return (TRUE);
-    if (chksqr(rw - 2, col - 1))
-	return (TRUE);
-    if (chksqr(rw + 1, col + 2))
-	return (TRUE);
-    if (chksqr(rw + 1, col - 2))
-	return (TRUE);
-    if (chksqr(rw - 1, col + 2))
-	return (TRUE);
-    if (chksqr(rw - 1, col - 2))
-	return (TRUE);
-    return (FALSE);
-}
-
-static int
-iabs(int num)
-{
-    if (num < 0)
-	return (-num);
-    else
-	return (num);
-}
+    play();
 
-static bool
-chksqr(int r1, int c1)
-{
-    if ((r1 < 0) || (r1 > BDEPTH - 1))
-	return (FALSE);
-    if ((c1 < 0) || (c1 > BWIDTH - 1))
-	return (FALSE);
-    return ((!board[r1][c1]) ? TRUE : FALSE);
+    endwin();
+    ExitProgram(EXIT_SUCCESS);
 }
-
-/* knight.c ends here */