我如何使用if语句来知道是玩家还是计算机赢了？

Question

我刚刚开始学习java，所以我可能还没有走上正确的道路，但我有一个任务，要求我创建一个21人的游戏。这个游戏的运行方式是玩家和计算机轮流输入1、2或3。输入一个满足或超过21的数字的玩家输。我似乎遇到的麻烦是，当输入最后一个数字时，我似乎不能让程序退出循环，它将显示玩家每次都会输，无论是赢是输。

我尝试过在do-while循环之后使用另一个if语句来显示"You Win!“或者“你输了”但是，我不知道应该在if语句中使用哪些参数来决定谁赢了。我也试着将游戏设置为玩家为偶数，计算机为奇数，但我无法将这些数字添加到运行总数中以结束循环。

  int numLoops = 0;
  int firstCheck;
  int points;
  Scanner input = new Scanner(System.in);

  do
  {
     System.out.print("\nEnter a 1, 2, or 3 >> ");
     points = input.nextInt();

     int random = (int )(Math.random() *  3 + 1);
     numLoops = points + numLoops + random;

     if(numLoops < 21)
     {
        System.out.println("The computer entered a " + random);         
        System.out.println("The new total is " + numLoops);
     }
     else
     {
        //This is what always prints.
        System.out.println("You lost! The computer is the victor.");
     }
  }while(numLoops < 21);
  //this is what I am having most of my trouble with.
  System.out.println("You Win!");

我预计循环将在总数达到21之后关闭，并将输出一条语句，该语句将根据谁获胜而有所不同。但是，程序总是输出玩家丢失的内容。

Answer 1

如果我做了一些改变来简化事情。看一下源代码，它应该有很好的文档，并且解释得很好。

/*
 * Which players turn is it?
 * (true for human player, false for computer)
 */ 
boolean isHumanPlayersTurn = true;
int totalPoints = 0;

Scanner input = new Scanner(System.in);

// the game ending condition
while (totalPoints < 21) {

    // take an action, depending on the players turn
    if (isHumanPlayersTurn) {
        System.out.print("\nEnter a 1, 2, or 3 >> ");
        totalPoints += input.nextInt();
    } else {
        int random = (int) (Math.random() * 3 + 1);
        System.out.println("The computer takes " + random);
        totalPoints += random;
    }

    System.out.println("Total amount is " + totalPoints);

    /*
     * Important part: After each players move, change the players turn, but do NOT
     * do this if the game already ended, since then the other player would have won.
     */
    if (totalPoints < 21) {
        isHumanPlayersTurn = !isHumanPlayersTurn;
    }
}

// now, the player to move is the one who loses
if (isHumanPlayersTurn) {
    System.out.println("You lost! The computer is the victor.");
} else {
    System.out.println("You Win!");
}

Answer 2

在用户输入数字后，您应该立即检查他们是否达到21 (并输出该点的总数)。如果21没有命中，那么计算机应该猜测，然后您再次检查是否命中了21。因此，您将有两个if语句(每次猜测后一个；user/computer)。在else块中，用户猜测是计算机要猜测的位置。您的if语句将检查>= 21，指示用户或计算机是否丢失。您不需要在循环外声明胜利器，因为这可以在循环内完成。

例如：

    int total = 0;
    do
    {
        System.out.print("\nEnter a 1, 2, or 3 >> ");
        points = input.nextInt();
        total = total + points;
        System.out.println("The new total is " + total);

        if (total >=21)
        {
            System.out.println("You lost! The computer is the victor.");
        }
        else
        {
            int random = (int )(Math.random() *  3 + 1);
            total = total + random;
            System.out.println("The computer entered a " + random);         
            System.out.println("The new total is " + total);

            if(total >= 21)
            {
                System.out.println("You Win!");
            }
        }
    }while(total < 21);