Fix null pointer in chooseMove method

src/Human.java

@@ -34,6 +34,7 @@ public class Human extends Player {
 
         int x = 0, y = 0;
         boolean pass = false;
+        GomokuCell cell = null;
 
         do {
 
@@ -61,7 +62,8 @@ public class Human extends Player {
                 }
             } while (!pass);
 
-            pass = board.get(x, y).isPlayable();
+            cell = board.get(y, x);
+            pass = cell == null ? false : cell.isPlayable();
             if (!pass) {
                 System.out.println("Cette case n'est pas jouable !");
             }
@@ -69,6 +71,6 @@ public class Human extends Player {
 
         System.out.println("Vous avez saisi : " + x + ", " + y);
 
-        return board.get(x, y);
+        return cell;
     }
 }