java - ArrayOutOfBounds 测试代码不起作用

Question

我在测试 arrayOutOfBounds 异常时遇到了问题。在下面的代码中，我的 if...else 语句应该阻止骑士离开我的棋盘，但我仍然遇到异常。有人在这里看到我的错误吗？感谢您的帮助!

public int[][] firstMoveChoice() {
int knight = 0;    
x += 1;
y += 2;

if (x > board.length) { // this tests to make sure the knight does not move off the row
    System.out.println("Cannot move off board on x axis");
    x -= 1;
}
else if (y > board.length) { // this tests to make sure the knight does not move off the column
    System.out.println("Cannot move off board on y axis");
    y -= 2;
}
else { // this moves the knight when the above statements are false
    board[x][y] = ++knight;
    System.out.println("This executed");
}

for(int[] row : board) {
    printRow(row);
}
}

这是最后打印的电路板:

This executed
1  0  0  0  0  0  0  0  
0  0  2  0  0  0  0  0  
0  0  0  0  3  0  0  0  
0  0  0  0  0  0  4  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 8
at knightstour.Moves.firstMoveChoice(Moves.java:53)
at knightstour.KnightsTour.main(KnightsTour.java:24)
Java Result: 1
BUILD SUCCESSFUL (total time: 0 seconds)

这是我的 ChessBoard 类:

public class ChessBoard {

int[][] board;

public ChessBoard() {
    this.board = new int[8][8];
}
}

这是我的 printRow 方法:

public static void printRow(int[] row) {
    for (int i : row) {
        System.out.print(i);
        System.out.print("  ");
    }
    System.out.println();
}

这是我的主要方法。当它调用起始位置时，它所做的只是将 board[0][0] 分配给 1。如果您需要实际代码，请告诉我。

public static void main(String[] args) {

    MoveKnight myKnight = new MoveKnight();
    myKnight.startingLocation();
    myKnight.firstMoveChoice();
    myKnight.firstMoveChoice();
    myKnight.firstMoveChoice();
    myKnight.firstMoveChoice(); // this moves the knight off the board
}

Answer 1

您的if 条件必须是'>='。尝试:

if (x >= board.length) { // This tests to make sure the knight does not move off the row
    System.out.println("Cannot move off board on x axis");
    x -= 1;
}
else if (y >= board.length) { // This tests to make sure the knight does not move off the column
    System.out.println("Cannot move off board on y axis");
    y -= 2;
}