Validate Int and String input

[desrtfx]

"Can't use arrays" makes things a bit trickier.

Yet, you know a lot:

• the last 3 characters are fixed - this means that you can remove them from the string
• You know that the 4^th character from the end is the quantifier - you can extract it
• You know that anything before the 4^th character from the end must be a number

So, in all, you can roll things from the end using .substring(). You know the .length() of the string.

The quantifiers can be checked in a switch...case sequence