面向对象原则 1002 9 Object Orientation Institute of Computer Software,Nanjing University 2022-2-27面向对象原则 Institute of Computer Software, Nanjing University 2022-2-27 9 Object Orientation E n c a p s ula tio n A b s t r a c tio n P oly m o r p his m In h e rit a n c e