Regex digits smaller then 82

Question

I'm trying to write a simple regex but I don't know why it is not working.

User enter 2 digits number like 01, 09, 23, 55, until 82. After 82 system will refuse.

Here is my regex, 2 digits must be smaller than 82.

0[1-9]|[1-8][0-9]|8[0-2]

Answer 1

You should have [1-7] for the range 10-79, not [1-8]. Don't forget the ^ and $ to specify the start and ending of the string:

^(0[1-9]|[1-7]\d|8[0-2])$

Answer 2

Why not cast to an integer and then just test x < 82?