为什么我的变量值永远不会改变？

Question

在我的代码中，我有变量randomNumber，它应该改变，但它从来没有。为什么？

import java.util.Random; 
import java.util.Scanner; 

public class NimGame 
{ 

    public static void main(String[] args) 
    { 
     Random myRandom = new Random(); 

     int playerCount = 1; 
     int stonesRemoved = 0; 
     int randomNumber; 

     randomNumber = myRandom.nextInt(15) + 16; // Selects a random number between 15-30 as the number of stones. 

     System.out.println("You will be playing with: " + randomNumber + " stones."); 

     System.out.println("Each player can take 1, 2 or 3 stones when it is your turn."); 
     System.out.println("Player who takes the last stone looses."); 
     System.out.println(); 

     Scanner input = new Scanner(System.in); 

     while (true) 
     { 
      StoneRemover (randomNumber, playerCount); 
      randomNumber = randomNumber - stonesRemoved; 

      System.out.println("There are now: " + randomNumber + " stones"); 

      if (randomNumber == 0) 
      { 
      if (playerCount == 1) 
      { 
       System.out.println("Player 1 lost!"); 
      } 

      else 
      { 
       System.out.println("Player 2 lost!"); 
      } 
      break; 
      } 
      playerCount ++; 

      if (playerCount > 2) 
      { 
      playerCount = 1; 
      } 
     } 
     input.close(); 
    } 

    public static int StoneRemover (int stonesRemoved, int playerCount) 
    { 
     Scanner input = new Scanner(System.in); 
     while (true) 
     {  
      System.out.print("How many stones does player " + playerCount + " want to take? "); 
      stonesRemoved = input.nextInt(); 
     if (stonesRemoved > 3 || stonesRemoved == 0) 
      { 
      System.out.println("You did not select a correct number of stones to remove."); 
      System.out.println("Try Again!!"); 
      } 

     else 
      { 
      break; 
      } 
     } 
     return stonesRemoved; 
    } 
} 

     //Every time I run the code, the randomNumber does not update to the new number after the user retrieves 1,2, or 3 stones. Why is this happening 

Answer 1

你不使用返回值从stonesRemoved功能：

stonesRemoved = StoneRemover(randomNumber, playerCount); 

或者你可以这样做：

randomNumber -= StoneRemover(randomNumber, playerCount); 

Answer 2

，因为你没有更改程序不能正常工作变量stonesRemoved。它始终保持为0！

“但是不！我在StoneRemover方法中改变了它！不是吗？”你可能会问。

你做那么什么位置：

stonesRemoved = input.nextInt(); 

是不改变你的主要方法，即使用stoneRemoved变量：

randomNumber = randomNumber - stonesRemoved; // <-- not this one! 

这是因为你通过了值而不是stonesRemoved该方法的参考，所以在StoneRemover方法内更改它对stonesRemoved var无效主要方法可行。你可以做的是这样的：

改变这一行：

StoneRemover (randomNumber, playerCount); 

这样：

stonesRemoved = StoneRemover (randomNumber, playerCount); 

，它应该工作！