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问个入门问题。

问个入门问题。# Java - 爪哇娇娃

j*g2007-11-12 08:11

1 楼

Which statement(s) are true? (Choose all that apply)
A. IS-A relationships always rely on inheritance.
B. IS-A relationships always rely on instance variables.
C. IS-A relationships always require at least two class types.
D. IS-A relationships always rely on polymorphism.
E. IS-A relationships are always tightly coupled.
答案是 A,C,D
A 简单。
我不明白另外两个
C 不一定非要class, 可以从一个接口继承阿。
D IS-A可以体现多态性，但是说always rely on好像太强了。
那位牛人指导一下？

P*e2007-11-12 08:11

2 楼

c:interface is an extreme class, all of whose instance methods are abstract
d:,应该不是吧，可能想说，是靠多太来体现si a

【在 j****g 的大作中提到】

: Which statement(s) are true? (Choose all that apply)
: A. IS-A relationships always rely on inheritance.
: B. IS-A relationships always rely on instance variables.
: C. IS-A relationships always require at least two class types.
: D. IS-A relationships always rely on polymorphism.
: E. IS-A relationships are always tightly coupled.
: 答案是 A,C,D
: A 简单。
: 我不明白另外两个
: C 不一定非要class, 可以从一个接口继承阿。

j*g2007-11-12 08:11

3 楼

我也觉得D要是反过来说就对了。

m*t2007-11-12 08:11

4 楼

C: Interfaces are essentially pure abstract classes.
D: Where you have inheritance, you have polymorphism.
But I really think all these statements need to be put into a context - say
in Java, C++, or just pure theoretical OO.

【在 j****g 的大作中提到】