为什么什么都没打印出来？

问题描述

我是python的新手，所以我认为这可能是个简单的问题，但这使我感到困惑。这是我的代码：

# Mike Fitzgibbon CS4250 Project4 implement class diagram
# define the class
class Product:
    # name is the name of the product
    name = None
    # price is how much the product costs
    price = None
    # discount percent is how much the discount is in percentages
    discountPercent = None
    # define the constructor

    def __init__(self,n,p,d):
        # initialize variables
        self.name = n
        self.price = p
        self.discountPercent = d

    # define get discount by returning the discount
    def getdiscountAmount(self):
        return self.discountPercent

    # define discount price by returning the discount percent times the price
    def getdiscountPrice(self):
        return self.discountPercent*self.price

    # define get description by creating description using field variables
    def getDescription(self):
        print("Name: "+self.name)
        print("Price: "+self.price)
        print("discount: "+self.discountPercent+"%")
        print("discount price: "+self.getdiscountPrice())
        
        
def __main__():
    p=Product("A",100,90.0)
    print(p.getDescription())

当我运行此代码时，什么都不会打印出来。为什么？我该如何解决？

解决方法

您需要添加；

if name == '__main__':
    main()

这样做的原因是您定义了main函数，但没有告诉计算机运行它。

要运行__main__()函数，可以将其添加到程序的末尾：

if __name__ == "__main__":
   __main__()

要打印值，请将print(p.getDescription())更改为p.getDescription()，因为在类中调用该函数将输出这些值。顺便说一句，您不能将int / float与str并置，因此您应该将int / float转换为字符串，例如print("Price: "+str(self.price))

printing python python-3.x