将单独的类的方法调用到另一个类中

Question

This small method is part of a very large program with many separate classes. The method below is meant to call in a portion of my Purchase class which keeps track of how much inventory is bought. However, although I have instantiated as follows above

 Purchase currentPurchase;

I continue to receive the errors "identifier is expected", and "cannot find symbol".

Method:

public double processPurchase(currentPurchase){

lemonsBought = currentPurchase.getNumLemonsBought();
iceBought = currentPurchase.getNumLemonsBought();
    cupsBought = currentPurchase.getNumCupsBought();
    sugarBought = currentPurchase.getNumSugarBought();

     lemonInventory += lemonsBought;
     iceInventory += iceBought;
     cupInventory += cupsBought;
     sugarInventory += sugarBought;
     money -= (.5 * lemonsBought) + (2 * iceBought) + (2 * cupsBought) + (0.25 * sugarBought);

    return currentPurchase;
 } 

Money is a separate pre-instantiated variable

Answer 1

您需要将标识符添加到您的函数中，否则java编译器将不知道它应该接收什么。

public double processPurchase(Purchase currentPurchase){

Answer 2

我认为你正在返回一个错误的变量currentPurchase，你已经将其作为一个参数传递而我甚至没有操纵它。你确定你需要这个变量或者钱也是一个双变量。