promotion

src/backend/Board.java

@@ -409,7 +409,26 @@ public class Board {
 		board[move.getFromY()][move.getFromX()].setY(move.getToY());
 		board[move.getToY()][move.getToX()] = board[move.getFromY()][move.getFromX()];
 		board[move.getFromY()][move.getFromX()] = null;
+		
+		for (int x = 0; x < colNum; x++) {
+		        for (int y = 0; y < lineNum; y++) {
+		            canPromote(x, y);
+		        }
+		}
 		this.states.add(toString());
 	}
 	
-}
+	ArrayList<Piece> promoPieces= new ArrayList<>();
+	boolean promotion;
+
+	private boolean canPromote(int x, int y) {
+	    if (board[y][x] != null && board[y][x].getType() == PieceType.Pawn) {
+	        boolean isWhite = board[y][x].isWhite(); // ✅ Declare 'isWhite' here
+	        if ((isWhite && y == 0) || (!isWhite && y == 7)) {
+	            board[y][x] = new Piece(isWhite, PieceType.Queen, x, y); // ✅ Now valid
+	            return true;
+	        }
+	    }
+	    return false;
+	        }
+	}

src/backend/Piece.java

@@ -1,5 +1,7 @@
 package backend;
 
+import java.util.ArrayList;
+
 public class Piece {
 
 	private int x;
@@ -45,4 +47,5 @@ public class Piece {
         this.y = piece.y;
     }
 
+	
 }

src/backend/PieceType.java

@@ -1,5 +1,7 @@
 package backend;
 
+import java.util.ArrayList;
+
 public enum PieceType {
 	Pawn, Rook, Knight, Bishop, Queen, King;