java - 试图获得未售出的拍品

我的代码是这样，但是我有一个问题，就是要卖出很多。我不想为lotNumber输入一个int，因为我想显示所有未售出的手。

我哪里做错了？

public ArrayList<Lot> getUnsold()
{
   for(Lot lot : lots)
   {
    Bid highestBid = lot.getHighestBid();
    lotNumber = lot.getNumber();
    Unsold = new ArrayList<Lot>();
      if (highestBid != null)
        {

            System.out.println("Lot number " + lotNumber + " is sold"); //retuern "Sold" is highestBid
        }
      else
        {
            System.out.println(lotNumber); //print bidder and highest bid value
        }
   }
   return Unsold;
}

最佳答案

您需要在for循环之前实例化Unsold（应该未售出）。并且您没有在Unsold块的else列表中添加任何内容。您需要将该批次添加到Unsold块中的else。

//assuming you are passing `lots` as parameter
    public List<Lot> getUnsold(List<Lot> lots)
    {
       List<Lot> unsold = new ArrayList<Lot>();
       for(Lot lot : lots)
       {
        Bid highestBid = lot.getHighestBid();
        lotNumber = lot.getNumber();
          if (highestBid != null)
            {

                System.out.println("Lot number " + lotNumber + " is sold"); //retuern "Sold" is highestBid
            }
          else
            {
                System.out.println(lotNumber); //print bidder and highest bid value
                unsold.add(lot); // you are missing this
            }
       }
       return unsold;
    }