A.多態(tài)創(chuàng)建的對象只能調(diào)用到父類聲明過的方法B.兩個(gè)不相關(guān)的類,對象類型能相互轉(zhuǎn)換C.向下轉(zhuǎn)型都能成功D.向上轉(zhuǎn)型需要類型的強(qiáng)制轉(zhuǎn)換
A.public class SubClass SuperClass{}B.public class SubClass extends SuperClass{}C.public class SubClass static SuperClass{}D.public class SubClass void SuperClass{}
A.“張三”,”李四”,“王五”B.3.5,“3.1”,5C.a,b,2D.true,0,1