如何使用if语句来了解播放器或计算机是否赢了？

Posted 2023-01-28

我刚刚开始学习java，所以我可能甚至没有走上正确的轨道，但我有一个任务要求我创建一个21的游戏。游戏的工作方式是玩家和计算机轮流进入1,2，或3.输入达到或超过21的数字的玩家。我似乎遇到的麻烦是，当输入最终数字时，我似乎无法让程序退出循环，并且它将显示玩家每次输掉，输赢。

我尝试在do-while循环后使用另一个if语句来显示“You Win！”或者“你失去了。”但是，我无法弄清楚我应该在if语句中使用哪些参数来决定谁赢了。我还尝试将游戏设置为偶数，将计算机设置为奇数，但我无法将数字添加到运行总计以结束循环。

  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，并将输出一个声明，根据谁获胜而变化。但是，程序总是输出玩家输了。

答案

如果做了一些改动以简化事情。看一下源代码，它应该有详细记录并最好地解释。

/*
 * 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!");

另一答案

在用户输入数字后，您应立即检查它们是否达到21（并且还输出该点的总数）。如果21没有被击中，那么计算机应该猜测，然后再次检查以查看21是否被击中。所以你将有两个if语句（每次猜测后一个;用户/计算机）。在用户猜测之后的else块中是计算机猜测的位置。您的if语句将检查> = 21，表示适当的用户或计算机丢失。你不需要在循环之外声明一个胜利者，因为这可以在循环中完成......

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);