需求工程的一道题目，熟悉点人的帮我解答下

[gameboy911]

You want to replace a function f with a more efficient function g. Provided f and g have identical signatures (prototypes), how do their specifications (in terms of pre-and post-conditions) have to relate for your program to remain correct?
a) Pre of g must be weaker than pre of f, but post of g must be stronger than post of f.
b) Pre of g must be stronger than pre of f, but post of g must be weaker than post of f.
c) Pre and post of g must be stronger than pre and post of f.
d) Pre and post of g must be weaker than pre and post of f.

我理解是功能g要代替f，前置条件肯定要弱于f,但是我不理解这里的post-conditions是指g对后面的条件，还是后面接口所需具备的条件
如果是前者，就应该是强于f,答案选A，如果后者就是弱于F，答案选D

有谁这方面比较熟，帮我解答下？

[M_song]

应该是A!

[antony0203]

确定吗？这可是考试题阿，错了就没了
最好能讲出点道道来，赫赫

[zhengdaolin]

你等级很高啊
[Quote=引用 2 楼 antony0203 的回复:]
确定吗？这可是考试题阿，错了就没了
最好能讲出点道道来，赫赫
[/Quote]

[antony0203]

哈哈，又碰到一个熟人，msn碰不到你，下次可以在这里在线聊