tictactoe

commit 7d8009aecfd298c86419f3e99249f9f08bc90e83
parent fe0f1f2cb5e0ae8e5656ce2e3136c392abcfed8b
Author: Wilson Gheen <wilson@wilsonrgheen.com>
Date:   Sat, 17 Dec 2022 15:11:27 -0600

Fix issue in get_near_wins that ignored some winning moves, and change name

Diffstat:
M
tictactoe.h
 | 
73
+++++++++++++++++++++++++++++++++++++++++++++----------------------------

1 file changed, 45 insertions(+), 28 deletions(-)
diff --git a/tictactoe.h b/tictactoe.h
@@ -13,8 +13,8 @@
 #define scase(s1, s2)    if (!strcmp(s1, s2))
 
 /*typedef void (*board_fn)(char *, char);*/
-static char the_desired_board[32];
-static int  srand_seeded = 0;
+static char  the_desired_board[32];
+static _Bool srand_seeded = 0;
 
 static int get_rand(int max_excl) {
     if (!srand_seeded) {
@@ -23,35 +23,52 @@ static int get_rand(int max_excl) {
     }
     return rand() % max_excl;
 }
-char get_near_wins(char *b, char *winning_moves) {
+char get_winner_or_winning_moves(char *b, char *winning_moves) {
     char center = b[4];
-    for(int i=-4; center != ' ' && i < 0; i++) {
-        int s2 = 4+i;
-        int s3 = 4-i;
-        if(b[s2] == center && b[s3] == center)
-            return center;
+    _Bool add_to_wm = 0; 
+    for(int i=-4; i < 0; i++) {
+        int sq1 = 4+i;
+        int sq3 = 4-i;
+        if(b[sq1] == b[sq3] && b[sq1] != ' ') {
+            if(b[sq1] == center)
+                return center;
+            if(center == ' ')
+                add_to_wm = 1;
+        }
         if(winning_moves == NULL) continue;
-        if(b[s2] == center || b[s3] == center) {
-            if(b[s2] == ' ')
-                winning_moves[s2] = center;
-            else if(b[s3] == ' ')
-                winning_moves[s3] = center;
+        if(add_to_wm) {
+            winning_moves[i] = b[sq1];
+            add_to_wm = 0;
+        }
+        else if(center == ' ') continue;
+        else if((b[sq1] == center) ^ (b[sq3] == center)) {
+            if(b[sq1] == ' ')
+                winning_moves[sq1] = center;
+            else if(b[sq3] == ' ')
+                winning_moves[sq3] = center;
         }
     }
     for(int i=1; i <= 7; i+=2){
-        if(b[i] == ' ') continue;
         int distance = ((i+1) & 4) ? 3 : 1;
-        int s2 = i - distance;
-        int s3 = i + distance;
-        if(b[s2] == b[i] && b[s3] == b[i]) {
-            return b[i];
+        int sq1 = i - distance;
+        int sq3 = i + distance;
+        if(b[sq1] == b[sq3] && b[sq1] != ' ') {
+            if(b[sq1] == b[i])
+                return b[i];
+            if(b[i] == ' ')
+                add_to_wm = 1;
         }
         if(winning_moves == NULL) continue;
-        if(b[s2] == b[i] || b[s3] == b[i]) {
-            if(b[s2] == ' ')
-                winning_moves[s2] = b[i];
-            else if(b[s3] == ' ')
-                winning_moves[s3] = b[i];
+        if(add_to_wm) {
+            winning_moves[i] = b[sq1];
+            add_to_wm = 0;
+        }
+        else if(b[i] == ' ') continue;
+        else if((b[sq1] == b[i]) ^ (b[sq3] == b[i])) {
+            if(b[sq1] == ' ')
+                winning_moves[sq1] = b[i];
+            else if(b[sq3] == ' ')
+                winning_moves[sq3] = b[i];
         }
     }
     return 0;
@@ -79,7 +96,7 @@ char get_move_preset_board(char *board, char player) {
     for(int i=0; i < 9; i++) {
         if(desired_board[i] == player && board[i] == ' ') {
             board[i] = player;
-            return get_near_wins(board, NULL);
+            return get_winner_or_winning_moves(board, NULL);
         }
     }
     return 0;
@@ -90,7 +107,7 @@ char get_move_from_human(char *board, char player) {
     tb_present();
     scanf("%d", &n);
     board[n-1] = player;
-    return get_near_wins(board, NULL);
+    return get_winner_or_winning_moves(board, NULL);
 }
 char get_random_move(char *board, char player) {
     int legal_moves[9];
@@ -99,13 +116,13 @@ char get_random_move(char *board, char player) {
         if(board[i] == ' ')
             legal_moves[lm_ind++] = i;
     board[legal_moves[get_rand(lm_ind)]] = player;
-    return get_near_wins(board, NULL);
+    return get_winner_or_winning_moves(board, NULL);
 }
 char get_winning_move_else_random(char *board, char player) {
-    char winning_moves[9] = {0};
+    char winning_moves[9] = "";
     int my_winning_moves[5];
     int mwm_ind = 0;
-    get_near_wins(board, winning_moves);
+    get_winner_or_winning_moves(board, winning_moves);
     for(int i=0; i < 9; i++)
         if(winning_moves[i] == player)
             my_winning_moves[mwm_ind++] = i;