java - 不确定这个类是如何工作的

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我目前必须制作一个玩 Chuck-a-Luck 游戏的程序。Chuck a Luck 是一款骰子游戏，玩家可以对三个六面骰子上出现的内容进行投注。玩家从钱包或钱包中的一定数量的欧元开始，可以下注小于或等于其钱包或钱包中当前欧元数量的任意整数欧元。下表显示了玩家可以下注的内容以及如果正确的话他们将赢得什么:

玩家可以继续玩游戏，直到钱包或钱包里的钱用完或决定停止玩为止。

Wallet theWallet = new Wallet();
double cash = 10;

JOptionPane.showMessageDialog(null,"You currently have €" + cash);

Object[] options = {"Any triple", "Big", "Field", "Small"};
int option = JOptionPane.showOptionDialog(null,"What type of bet would you like to place" , "Chuck-a-Luck", JOptionPane.YES_NO_OPTION,  JOptionPane.QUESTION_MESSAGE,null,options,null);

String input = JOptionPane.showInputDialog("How much money would you like to bet? ");
Scanner scanner = new Scanner(input);
double money = scanner.nextInt();
scanner.close();

boolean enoughMoney = theWallet.get(money);

这是我在主线中的代码，这是钱包类本身。

public class Wallet { // Wallet data type 
   // current cash in wallet 
   private double cash;  // invariant: cash >= 0.0 

   // construct wallet with zero cash 
   public Wallet() { cash = 0.0; } 

   // put an amount of money into wallet 
   // pre-condition: money > 0.0 
   public void put(double  money) { 
      assert money > 0.0 : "Wallet put method: pre-condition violated!"; 
      if (money > 0.0) cash = cash + money; 
   } 

   // get an amount of money from wallet 
   // returns true if wallet had enough cash, false otherwise 
   // pre-condition: money > 0.0 
   public boolean get(double money){ 
      assert money > 0.0 : "Wallet get method: pre-condition violated!"; 
      if (money > 0.0 && cash >= money) { 
         cash = cash - money; 
         return true; 
      } 
      return false; 
   } 

   // return current amount of cash in wallet 
   public double check() { return cash; } 

   // convert to a String data type value 
   public String toString() { 
      return getClass().getName() + "[cash = " + cash + "]"; 
   } 

} // end Wallet data type   

我投入的任何有效投注都会返回 false 的 boolean 结果，而它应该是 true。假设我有 10 英镑，我下注 5 英镑，它在应该返回 true 的地方返回 false。关于什么不起作用的任何想法？谢谢

Answer 1

您必须先在钱包里存一些钱:

Wallet theWallet = new Wallet(); 
double cash = 10;
theWallet.put(cash);

请记住 cash main 中的变量方法与 cash 不一样Wallet 内的类变量类:

public class Wallet { // Wallet data type 
   // current cash in wallet 
   private double cash;  // invariant: cash >= 0.0 

   // construct wallet with zero cash 
   public Wallet() { cash = 0.0; } 

   //rest of code  
}