Suppose today is Monday,
See you in two days. >>> It is impossible to meet you on Tuesday or Wednesday >>> See you after two days.
See you within two days. >>> Maybe meet you tomorrow or on Wednesday. >>> See you again before Thursday.
Could anyone tell me my understanding of these are correct or not?
If today is Monday and I say "See you in 2 days" that means I will see you Wednesday. It is more common to say "the day after tomorrow" instead of 2 days.
If today is Monday and I say "See you within 2 days" that means I will see you before Wednesday. I would never say "see you within 2 days" though, I would say "see you sometime before Wednesday."