#！/usr/bin/env python
# _*_ coding utf-8 _*_
#Author: aaron

import abc


class Operation(object):
    def __init__(self, NumberA=0, NumberB=0):
        self.NumberA = NumberA
        self.NumberB = NumberB

    def GetResult(self):
        pass


class AddOp(Operation):
    def GetResult(self):
        return self.NumberB + self.NumberA


class MinusOp(Operation):
    def GetResult(self):
        return self.NumberA - self.NumberB


class MultiOp(Operation):
    def GetResult(self):
        return self.NumberA * self.NumberB


class DivideOp(Operation):
    def GetResult(self):
        try:
            return 1.0 * self.NumberA / self.NumberB
        except ZeroDivisionError:
            raise


class Factory(metaclass=abc.ABCMeta):

    @abc.abstractmethod
    def create_factory(self):
        ‘‘‘工厂类抽象接口‘‘‘


class AddFactory(Factory):
    def create_factory(self):
        return AddOp()


class MinusFactory(Factory):
    def create_factory(self):
        return MinusOp()


class MultiFactory(Factory):
    def create_factory(self):
        return MultiOp()


class DivideFactory(Factory):
    def create_factory(self):
        return DivideOp()


if __name__ == ‘__main__‘:
    ch = ‘‘
    while not ch == ‘q‘:
        NumberA = eval(input(‘Please input number1:  ‘))
        op = str(input(‘Please input the operation:  ‘))
        NumberB = eval(input(‘Please input number2:  ‘))

        if op == ‘+‘:
            OPFactory = AddFactory()
        elif op == ‘-‘:
            OPFactory = MinusFactory()
        elif op == ‘*‘:
            OPFactory = MultiFactory()
        elif op == ‘/‘:
            OPFactory = DivideFactory()
        else:
            print(‘invilid input!‘)

        oper = OPFactory.create_factory()
        oper.NumberA = NumberA
        oper.NumberB = NumberB
        print(‘The result is:‘, oper.GetResult())
        print(‘\n#--  input q to exit any key to continue‘)
        try:
            ch = str(input())
        except:
            ch = ‘‘