Java石头剪刀布

Question

我知道这里已经一次又一次地询问这个java作业，但是我不想复制其他方法(因为似乎有很多方法可以编写此类代码)，我宁愿需要有关矿井的帮助，这样我就可以更轻松地理解这些概念。而且，教授也许很容易检查我是否作弊，哈哈。

这段代码没有错误，但是它没有像预期的那样工作。输出真的是......随机的。

我觉得我错过了一整段代码，但我一遍又一遍地阅读我的教科书，似乎无法发现错误的根源。 :|请帮忙!

编辑:我用固定的更改更新了我的帖子很多。

import java.util.Scanner;

public class RockPaperScissors
{
   public static void main(String[] args)
     {  
      String playerTwo = "";\\to be honest I'm not sure what this is even for

      Scanner keyboard = new Scanner(System.in);
      System.out.println("Lets play rock-paper-scissors! Please enter your move:");

      int Choice = (int) (Math.random()*2);
         if (Choice == 0)
            playerTwo = "ROCK";\\rock = 0
         else if (Choice == 1)
            playerTwo = "PAPER";\\paper = 1
         else if (Choice == 2)
            playerTwo = "SCISSORS";\\scissors = 2

  String playerOne = keyboard.nextLine();     
     playerOne = playerOne.toUpperCase();
        if (playerOne.equals(playerTwo)){
              System.out.println("It's a tie, so nobody wins!");
              }

        if (playerOne.equals("ROCK")){
              if (playerTwo.equals("PAPER")){
                 System.out.println("Your rock got covered by my paper. You lose!");
                 }
              if (playerTwo.equals("SCISSORS")){
                 System.out.println("Your rock smashes my scissors. You win!");
                 }
              }

        if (playerOne.equals("PAPER")){
              if (playerTwo.equals("ROCK")){
                 System.out.println("Your paper covers my rock. You win!");
                 }
              if (playerTwo.equals("SCISSORS")){
                 System.out.println("Your paper got cut by my scissors. You lose!");
                 }
              }

        else if (playerOne.equals("SCISSORS")){
              if (playerTwo.equals("ROCK")){
                 System.out.println("Your scissors got smashed by my rock. You lose!");
                 }
              if (playerTwo.equals("PAPER")){
                 System.out.println("Your scissors cut my paper. You win!");
                 }
              }

            else
                  System.out.println("Error. Please restart and enter either: \"rock\", \"paper\", or \"scissors\".");
   }
}

Answer 1

在我弄清楚您的代码有什么问题之前，这里有一些建议:

Math.round() 不是必需的。如果您要转换为 int 类型，那么它将自动舍入到最接近的整数。

您应该声明一个包含三种类型结果的枚举。然后您可以通过名称而不是数字或字符串来引用它们:

public enum Outcome { ROCK, PAPER, SCISSOR };

现在您可以分配变量并使用 switch 语句:

Outcome player1 = Outcome.ROCK;
// switch statement example
switch (player1) {
    case ROCK:
        // do something
    case PAPER:
        // do something
    case SCISSOR:
        // do something

此外，注释是用两个正斜杠完成的，而不是反斜杠

现在看看代码中的 WTF 时刻。这到底是什么:

if (playerOne.equals("ROCK")){}
              else if (playerTwo.equals("PAPER")){
                 System.out.println("Your rock got covered by my paper. You lose!");
                 }
              else if (playerTwo.equals("SCISSORS")){
                 System.out.println("Your scissors got smashed by my rock. You win!");
                 }

基本上，您只是告诉计算机，如果playerOne 选择摇滚，则不执行任何操作。 if语句的语法如下:

if (condition) {
     // do something 
}

如果您想在一个 if 语句中包含多个 if 语句，请执行以下操作:

if (condition) {
    if (condition) { // do something }
    else if (condition) { // do something else if first did not work }
    else { // do something if nothing worked }
}

在您的代码中输入以下内容:

if (condition) {} // this does nothing if condition is true
else if (condition) {...} // if the first if statement is true, this will not be reached
else if (condition) {...} // neither will this!

因此，要解决您的问题，您的代码片段需要如下所示:

if (playerOne.equals("ROCK")) {
              if (playerTwo.equals("PAPER")) {
                 System.out.println("Your rock got covered by my paper. You lose!");
              }
              else if (playerTwo.equals("SCISSORS")) {
                 System.out.println("Your scissors got smashed by my rock. You win!");
              }
} // terminates outer if

如果您还有其他问题，请对此答案发表评论!