小编Wil*_*ell的帖子

我得到了一个学校作业,这是对面向对象编程的介绍.我真的很接近解决这个问题,我猜这个语法有些问题.也许你们中的一些专业人员确切知道问题是什么？

我上课了:

class CashRegister():
    __taxRate = 0
    __numProductsSold = 0
    __totalRevenue = 0.0
    __taxAmount = 0.0
    __soldProducts = []

    def __init__(self, taxRate):
        self.__taxRate = taxRate

    def getNumProductsSold(self):
        return self.__numProductsSold

    def getTotalRevenue(self):
        return self.__totalRevenue

    def getTaxAmount(self):
        return self.__taxAmount

    def getSoldProducts(self):
        return self.__soldProducts

    def addItem(self, product, price):
        self.__numProductsSold +=1
        self.__totalRevenue += price
        self.__taxAmount += price * self.__taxRate
        self.__soldProducts.append(product)

我试着在这里打电话:

import CashRegister

def main():
    testRegister = CashRegister(22)
    testProduct = "Mat"
    testRegister.addItem(testProduct, 23.99)
    print testRegister.getTotalRevenue ()

if __name__ == '__main__':
    main();

有谁发现了这个问题？如标题所示获取错误消息.