-- coding: utf-8 --

class Screen(object): @property def width(self): return self._width

@width.setter
def width(self,value):
    if isinstance(value,int) and value >= 0:
        self._width = value
    else:
        raise ValueError('width只能为正整数')

@property
def height(self):
    return self._height

@height.setter
def height(self,value):
    if isinstance(value,int) and value >= 0:
        self._height = value
    else:
        raise ValueError('height只能为正整数')

@property
def resolution(self):
    return self._width * self._height

test:

s = Screen() s.width = 1024 s.height = 768 print(s.resolution) assert s.resolution == 786432, '1024 * 768 = %d ?' % s.resolution