Write a program that checks the properness of a given variable name. More specifically, your
program should specify whether a user-entered variable name is (1) illegal, (2) legal, but uses poor
style, or (3) good. There are different opinions as to what constitutes good style for a variable name.
For this program, check for good style using these rules:

 Only use letters and digits.
 Use a lowercase letter for the first character.

You don’t need to check for an uppercase letter for the first letter in the second word, third word, etc.

Sample session:

This program checks the properness of a proposed Java variable name.
Enter a variable name (q to quit): streetAddress2
Good!
Enter a variable name (q to quit): street address2
Illegal.
Enter a variable name (q to quit): StreetAddress2
Legal, but uses poor style.
Enter a variable name (q to quit): 2ndStreetAddress
Illegal.
Enter a variable name (q to quit): street$address$2
Legal, but uses poor style.
Enter a variable name (q to quit): q