Single Link List之Insert及Delete Node

1.insert
I.new個node
II.將此node的data設為”item”
III.t—>Link設為x—>Link
IV.x—>Link設為t

2.delete x(假設s指向y，y指向x)
I.若y == Nil則s = x.link
II.否則，y.link = x.link
III.ret(x)