Can I say "you don't need to come"?
here is a sentence:
you can come with me if you like but you needn't come if you don't want to. is it correct?
or, .... but you don't need to come if you don't want to.
thanks a lot.

Question

Can I say "you don't need to come"?
here is a sentence: 
you can come with me if you like but you needn't come if you don't want to. is it correct? 
or, .... but you don't need to come if you don't want to.      
thanks a lot.

Answer

Correct.  The second one sounds a bit more natural.

Answer

Both are correct. It's possible to use "need" as a modal verb, especially in the negative form.

Answer

need作情态动词用于疑问句与否定句，在肯定句中表主动是need to do。原句应改为You need not come.就行。

Answer

Both are correct actually.