超载方法

Question

  //*******************************************************
// FlexibleAccount.java
//
// A bank account class with methods to deposit to, withdraw from,
// change the name on, and get a String representation
// of the account.
//*******************************************************
import java.util.Random;
public class FlexibleAccount
{
  private double balance;
  private String name;
  private long acctNum;

  //----------------------------------------------
  //Constructor -- initializes balance, owner, and account number
  //----------------------------------------------
  public FlexibleAccount(double initBal, String owner, long number)
  {
    balance = initBal;
    name = owner;
    acctNum = number;
  }

  public FlexibleAccount(double initBal, String owner, double number)
  {
    Random generator = new Random();
     balance = initBal;
    name = owner;
     number=generator.nextDouble();
     this.acctNum= number;
    }

    public FlexibleAccount(String owner)
    {
     balance = 0;
     name=owner;
     Random generator = new Random();
     number=generator.nextDouble();
     this.acctNum= number;
     }
  //----------------------------------------------
  // Checks to see if balance is sufficient for withdrawal.
  // If so, decrements balance by amount; if not, prints message.
  //----------------------------------------------
  public void withdraw(double amount)
  {
    if (balance >= amount)
       balance -= amount;
    else
       System.out.println("Insufficient funds");
  }

  public void withdraw(double amount,int fee)

  {
   if(balance>=amount)
    balance-= amount+fee;
    else
        System.out.println("Insufficient funds");
    }   

  //----------------------------------------------
  // Adds deposit amount to balance.
  //----------------------------------------------
  public void deposit(double amount)
  {
    balance += amount;
  }

  //----------------------------------------------
  // Returns balance.
  //----------------------------------------------
  public double getBalance()
  {
    return balance;
  }


  //----------------------------------------------
  // Returns a string containing the name, account number, and balance.
  //----------------------------------------------
  public String toString()
  {
    return "Name: " + name + 
"\nAccount Number: " + acctNum +
"\nBalance: " + balance; 
  }
}

这就是我所拥有的，我试图将FlexibleAccount超载3次，如下所示

1. public FlexibleAccount（double initBal，String owner，long number） - 按指定初始化余额，所有者和帐号
2. public FlexibleAccount（double initBal，String owner） - 按指定初始化余额和所有者;随机生成帐号。
3. public FlexibleAccount（String owner） - 按指定初始化所有者;将初始余额设置为0并随机生成帐号。

当我编译时我得到这些错误

 FlexibleAccount.java:31: possible loss of precision
    found   : double
    required: long
         this.acctNum= number;
                       ^
    FlexibleAccount.java:39: cannot find symbol
    symbol  : variable number
    location: class FlexibleAccount
         number=generator.nextDouble();
         ^
    FlexibleAccount.java:40: cannot find symbol
    symbol  : variable number
    location: class FlexibleAccount
         this.acctNum= number;
                   ^

如何解决这个问题，这是正确的重载方法吗？

Answer 1

就像上一个问题一样 - 当你在number中写acctNum = number;时，没有这样的变量public FlexibleAccount(String owner)：

public FlexibleAccount(String owner)
    {
     balance = 0;
     name=owner;
     Random generator = new Random();
     number=generator.nextDouble();        << number is not declared
     this.acctNum= number;
     }

修改 这是你的第二个构造函数：

 public FlexibleAccount(double initBal, String owner, double number)
  {
    Random generator = new Random();
     balance = initBal;
    name = owner;
     number=generator.nextDouble();
     this.acctNum= number;
    }

出于某种原因，你用3个参数声明它，尽管你写道你希望它只接收2个参数 -

  

public FlexibleAccount（double   initBal，String owner） - 初始化   指定的余额和所有者;   随机生成帐号。

我想你想要变量号......它应该是更像这样的东西：

 public FlexibleAccount(double initBal, String owner)
      {
        Random generator = new Random();
         balance = initBal;
        name = owner;
         this.acctNum= generator.nextLong();
        }

现在正如你在上一篇中说的那样。问题这是一个功课，所以我不会添加。阅读你到目前为止所得到的答案和评论并进行处理。