java - 如何检查和结束一个由零和叉组成的二维数组 (Java)

Question

我使用 2D 数组和循环制作了一个圈和十字游戏(代码如下)。我想在数组满后结束游戏。我尝试过 if 语句，例如 if (board[row][col] = '.') 但我被告知这是不兼容的，因为它无法转换为 boolean 值。我的另一个想法是计算数据条目数并在 9 次后结束。然而，我是java新手，正在努力做这些，谁能告诉我一旦数组满了如何结束游戏？

public static void main(String[] args) {

    // TODO code application logic here
    Scanner scanner = new Scanner(System.in);

    // declare and intitialise the board
    char[][] board = new char[3][3];

    // initialise all the elements to '.' we use this to indicate that a 
    // square is empty, because a space character would not be visible
    for (int row = 0; row < board.length; row++) {
        for (int col = 0; col < board[row].length; col++) {
            board[row][col] = '.';  
        }
    }

    //The first player is X
    int placeRow;
    int placeCol;        
    char thisPlayer = 'X';
    boolean finished = false;

    while (!finished) {

        //Display the board
        for (int row = 0; row < board.length; row++) {
            for (int col = 0; col < board[row].length; col++) {
                System.out.print(board[row][col]);
            }

            System.out.println();
        }

        // Ask the user where to place the next character
        System.out.println("Character to be placed is " + thisPlayer);
        System.out.print("Enter the row at which you wish to place it> ");
        placeRow = scanner.nextInt();
        System.out.print("Enter the column at which you wish to place it> ");
        placeCol = scanner.nextInt();
        if (placeRow < 0 || placeRow > 2 || placeCol < 0 || placeCol > 2  ) {
            finished=true;
        }

        while (!finished) {

            //Display the board
            for (int row = 0; row < board.length; row++) {
                for (int col = 0; col < board[row].length; col++) {  

                }
                System.out.println();
            }  
            board[placeRow][placeCol] = thisPlayer;
            thisPlayer = (thisPlayer == 'X') ? 'O' : 'X';
            break;
        }
    }
}

Answer 1

if 子句中的不兼容类型

I've tried an if statement such as if (board[row][col] = '.') however i'm told this is incompatible as it can't be converted to a boolean.

您已被告知，因为 = 是赋值 运算符。

为了检查相等性，您应该使用 == equal to 运算符:

if (board[row][col] == '.') {
    /* do smth */
}

我建议阅读以下有关运算符的文章:

• Assignment, Arithmetic, and Unary Operators
• Equality, Relational, and Conditional Operators

棋盘已满时如何停止执行

count the data entries and end it after 9 goes

你的想法是正确的，你只需在每次迭代结束时遍历面板(就像打印其内容时一样)，并使用 != not equal 运算符检查单元格是否包含除点之外的任何内容。

// your external loop
while (!finished) {

    /* Displaying the board, prompting for inputs */

    // Calculating number of data entries across the board
    int dataEntries = 0;
    for (int row = 0; row < board.length; row++) {
        for (int col = 0; col < board[row].length; col++) {
            if (board[row][col] != '.') {
                dataEntries ++;
            }
        }
    }

    // Break loop if there are 9 data entries
    if (dataEntries > 8) {
        System.out.println("Board is full, game over.");
        break;
    }
}