java - 为什么循环不会停止迭代？

Question

我是一名 Java 初学者，为我的类(class)编写一个 gui tic-tac-toe 程序。 (没有玩家，只是计算机生成的)。

我的程序中的所有内容都按预期运行，除了一件事；看来我对 checkWinner 的方法调用的放置位置不正确，因为 X 和 O 的分配总是完成。为什么循环不会在产生胜利者后立即结束？

它将根据方法调用返回正确的获胜者，但 for 循环将继续迭代并填充其余部分(因此有时看起来 x 和 o 都获胜，或者一个获胜两次)。我快疯了，认为这可能是我的 checkWinner 方法调用和 if 语句的位置。当我设置 winner = true; 时，不应该取消循环吗？我尝试将它放在每个 for 循环之间、内部和外部，但没有成功:(

我已经标记了我认为有问题的区域//这里出了什么问题？//位于代码该部分的右侧。感谢您的任何意见! :)

  public void actionPerformed(ActionEvent e)
  {
    int total = 0, i = 0;
    boolean winner = false;


    //stop current game if a winner is found
    do{

      // Generate random # 0-1 for the labels and assign 
      // X for a 0 value and O for a 1 value

      for (int row = 0; row < gameboard.length; row++) //rows
      {
        for (int col = 0; col < gameboard[row].length; col++) //columns
        { 

          //Generate random number
          gameboard[row][col] = (int)(Math.random() * 2);  

          //Assign proper values
          if(gameboard[row][col] == 0)
          {
            labels[i].setText("X");
            gameboard[row][col] = 10; //this will help check for the winner
          }

          else if(gameboard[row][col] == 1)
          {
            labels[i].setText("O");   
            gameboard[row][col] = 100; //this will help check for winner
          }             


          /**Send the array a the method to find a winner
            The x's are counted as 10s
            The 0s are counted as 100s
            if any row, column or diag = 30, X wins
            if any row, column or diag = 300, Y wins
            else it will be a tie
            */

          total = checkWinner(gameboard);      **//Is this okay here??//**
          if(total == 30 || total == 300)        //
            winner = true;                //Shouldn't this cancel the do-while?


          i++; //next label

        }
      }//end for
    }while(!winner);//end while



    //DISPLAY WINNER
    if(total == 30)
      JOptionPane.showMessageDialog(null, "X is the Winner!");
    else if(total == 300)
      JOptionPane.showMessageDialog(null, "0 is the Winner!");
    else
      JOptionPane.showMessageDialog(null, "It was a tie!");
  }

Answer 1

最简单的方法是立即打破所有循环。 (即使有些人不喜欢这样)

outerwhile: while(true){

  // Generate random # 0-1 for the labels and assign 
  // X for a 0 value and O for a 1 value

  for (int row = 0; row < gameboard.length; row++) //rows
  {
    for (int col = 0; col < gameboard[row].length; col++) //columns
    { 

      total = checkWinner(gameboard);     
      if(total == 30 || total == 300)        
        break outerwhile;  //leave outer while, implicit canceling all inner fors.


      i++; //next label
    }
  }//end for
}//end while

然而，这不允许“平局”选项，因为如果没有找到获胜者，则基本上会重新开始游戏。为了允许平局，您根本不需要外部 while，并且当找到获胜者时可以立即保留两个 for:

  Boolean winner = false;
  outerfor: for (int row = 0; row < gameboard.length; row++) //rows
  {
    for (int col = 0; col < gameboard[row].length; col++) //columns
    { 

      total = checkWinner(gameboard);     
      if(total == 30 || total == 300){        
        winner = true;     
        break outerfor;  //leave outer for, implicit canceling inner for.

      }

      i++; //next label
    }
  }//end for

  if (winner){
    //winner
  }else{
     //tie.
  }