java - 更改数组中的值

Question

好的，这是我的代码(主要方法和我试图调用的方法) 我希望我的方法“rotateRR”基本上从 board[0] 获取值并将其放在 [1] 上，并继续对单行执行此操作。例如:

旧数组 -> [1][2][3][4][5] 变为 [5][1][2][3][4] <- 新数组应该是什么样子。

但是在我调用我的方法之后，我输入的常规输入应该是“1 rr”，但它返回相同的数组。我需要从rotateRR 方法返回更新后的数组，但它不允许我添加返回语句。

公共(public)课Numbrosia { static int [][] board = new int[5][5];

public static void main(String [] args){
    Scanner scan = null;

    try{
        scan = new Scanner(new File("input.txt"));
    }
    catch (FileNotFoundException e){
        e.printStackTrace();
        return;

    }

    for(int i = 0; i < board.length; i++){
        for(int j = 0; j < board.length; j++){
            board[i][j] = scan.nextInt();

        }
    }


    Scanner input = new Scanner (System.in);
    while (true){
    showBoard();

    System.out.println("What's your move?"); 
    int rowOrCol = input.nextInt();
    String action = ("");
    action = input.nextLine();

    if (action.equals(rowOrCol + " rr")){
        rotateRR(board);
        System.out.println("The new board looks like: ");
                    //Im guessing I should put something here?
         }

    }

}

public static void showBoard(){
    for(int row = 0; row < board.length; row++){
        for(int col = 0; col < board.length; col++){
            System.out.print(board[row][col] + " ");
        }
        System.out.println(" ");

        }



}

//METHODS 

public static void rotateRR (int [][] board){ 
    int[] temp = board[0];
    for (int i = 0; i < board.length + 1; i++){
        board[i] = board[i+1];
        }
    board[board.length + 1] = temp;
    }
//Its not letting me add a "return" type, tells me it is a syntax error on and an invalid type 

Answer 1

该方法的主要问题是它甚至没有执行您所描述的功能:

public static void rotateRR (int [][] board){ 
    int[] temp = board[0];
    for (int i = 0; i < board.length + 1; i++){
        board[i] = board[i+1];
    }
    board[board.length + 1] = temp;
}

应改为:

public static void rotateRR (int [][] board){ 

    // Saves the last entry of board, because 
    // each entry should be shifted to the right
    int[] temp = board[board.length - 1];

    // Here you should only run till board.length - 2, because
    // if you add 1 to i for accessing the next entry
    // you can maximal access the entry with number board.length - 1
    for (int i = 0; i < board.length - 1; i++){
        board[i] = board[i+1];
    }

    // Set the first entry to temp
    board[0] = temp;
}

因此，在该方法之后，您作为参数插入的数组将按照您上面描述的方式进行更改。请注意，您不需要返回类型，因为更改会影响原始数组(关键字按引用调用)。