I am new to web development.
I am still on planning stage. One of the question that bug me is, lets say: the username can only contains 8 characters and each characters is not allowed special characters (@#$%^&), it only allows lower case "a-z", upper case "A-Z", and numerical number from "0-9". How many users I can have and how do u calculate it?
Case 1: Characters cannot be repeated eg "abcdefgh", "a1b2c3d4" etc
Case 2: Characters can be repeated, eg. "AAbbccdd", "a1b1c1D1" etc
FYI, the 8 just a sample number, of course the bigger number I provide, the better it is, but I am just curious and my math sucks :(
(I assume, need to use permutations??)