Today we learned about the Fundamental Counting Principle (see p227) and I left you with one question to complete for homework:
“You have to choose a password for a web service. It must be exactly 8 characters long. The characters may be digits (0-9), uppercase letters, or lowercase letters. You may repeat characters. How many unique passwords are possible?”
Examples of unique passwords:
See how the last two are different? Passwords are case-sensitive, meaning that upper- and lowercase letters are distinct.