How to write a backgammon game program using JavaScript

The backgammon game is a very classic chess game that has a long history in modern society. With the rapid development of computer technology and the Internet, people can now play online backgammon through online platforms. In implementing these applications, JavaScript, as a popular programming language, naturally has to be mentioned.

How to use JavaScript to write a backgammon game program? In this article, the author will provide you with a basic program implementation idea, and give a concise and clear flow chart based on the implementation idea.

1. Program implementation ideas

1. Generate chessboard

As a chess game, the core of the backgammon game is of course the chessboard. In JavaScript, we can use HTML and CSS to generate a simple chessboard. The code is as follows:

nbsp;html>

  
    <meta>
    <title>五子棋游戏</title>
    <style>
      #chessboard {
        width: 540px;
        height: 540px;
        margin: 0 auto;
        border: 1px solid #333;
        position: relative;
      }
      .row {
        height: 30px;
        position: absolute;
        left: 0;
        right: 0;
      }
      .col {
        width: 30px;
        height: 30px;
        float: left;
        border: 1px solid #333;
      }
    </style>
  
  
    <div>
      <div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      <div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
      </div>
      ...
    </div>
    <script></script>
  

In the above code, we use the <div> tag as the basic element of the chessboard and use CSS to style it. Generate a chessboard with 10 rows and 10 columns through nested loops. <ol start="2"><li>Add chess pieces</li></ol> <p>After generating the chessboard, we need to be able to add black or white pieces to the chessboard. This requires us to use JavaScript to implement event binding. </p> <p>The method is as follows: </p> <p>1) Use the variable <code>turn to represent the current player, 0 represents black stones, 1 represents white stones:

var turn = 0; // 当前下棋方，0代表黑子，1代表白子

2) Use the document.getElementById method to obtain all the chessboard grids, and add a click event:

var cells = document.getElementsByClassName('col');
for (var i = 0, len = cells.length; i <p> Among them, the <code>addChessman</code> function represents the operation of adding chess pieces. </p><p>3) In the <code>addChessman</code> function, we need to perform the following operations: </p>

• Add chess pieces to the current grid. If there are already chess pieces, no more can be added. ;
• Switch the color of the chess piece to the opponent's color;
• Determine whether the current chess game has ended, and output victory information if it wins.

The core code is as follows:

// 添加棋子
function addChessman(cell) {
  if (cell.className.indexOf('chessman') === -1) {
    // 当前格子中没有棋子，则可以添加
    var chessman = document.createElement('div');
    chessman.className = (turn === 0) ? 'black chessman' : 'white chessman';
    cell.appendChild(chessman);

    // 切换下棋方
    turn = (turn === 0) ? 1 : 0;

    // 判断是否胜利
    if (checkWin(cell)) {
      alert('游戏结束，' + ((turn === 0) ? '黑子' : '白子') + '胜利！');
    }
  }
}

3. Judge the outcome

The last question is how to determine whether the game is won. In fact, the rules for determining the outcome of Gobang are very simple. You only need to search for five consecutive chess pieces around the current chess piece.

The specific operations are as follows:

1) Use the getRow function to get the number of rows in the current grid:

function getRow(cell) {
  var row = cell.parentNode;
  while (row.nodeName === 'DIV' && row.className.indexOf('row') === -1) {
    row = row.parentNode;
  }
  return parseInt(row.className.replace(/^row/, ''));
}

2) Use getCol The function gets the number of columns of the current grid:

function getCol(cell) {
  return parseInt(cell.className.replace(/^col/, ''));
}

3) Use the getChessman function to get the color information of the chess piece at the specified position on the chessboard:

// 获取棋盘上指定位置的棋子颜色信息
function getChessman(row, col) {
  var cell = document.querySelector('.row' + row + ' .col' + col);
  if (cell && cell.firstChild && cell.firstChild.tagName === 'DIV') {
    return cell.firstChild.className;
  } else {
    return null;
  }
}

4) Use the checkLine function to search all directions around the current position to see if there are five consecutive chess pieces:

// 检查棋子是否连成五个
function checkLine(row, col, offsetX, offsetY, count) {
  if (count === 5) {
    return true;
  } else if (row  10 || col  10) {
    return false;
  } else if (getChessman(row, col) === getChessman(row + offsetX, col + offsetY)) {
    return checkLine(row + offsetX, col + offsetY, offsetX, offsetY, count + 1);
  } else {
    return false;
  }
}

// 判断当前棋局是否结束
function checkWin(cell) {
  var row = getRow(cell);
  var col = getCol(cell);
  var flag = checkLine(row, col, 0, 1, 1) || // 水平方向
             checkLine(row, col, 1, 0, 1) || // 垂直方向
             checkLine(row, col, 1, 1, 1) || // 右斜方向
             checkLine(row, col, -1, 1, 1);  // 左斜方向
  return flag;
}

2. Flow chart

The flow chart to implement the backgammon program is as follows :

As above, when the user clicks on a blank area on the chessboard, the program will perform the following operations:

1. Determine whether there is a chess piece at the current position , if there is, no operation will be performed;
2. Add the chess piece of the corresponding color at the current position;
3. Judge whether the current game is successful, and if it is successful, output the victory information;
4. Switch Chess side, waiting for the next operation.