Pre-Lecture Prep and Pre-Quiz

Please read the Bitwise Operators section before class and complete the pre-quiz.

Announcements

• Homework 3 is due today.
• Homework 4 is due next Tuesday at 11:40am EDT.
• Two+ weeks until the midterm:
  • there will be a review session Tuesday 10/13 with the midterm Thursday 10/15
  • we will go over more details in the next few classes
• A short note on asking questions and help sessions
• Office hours and wizard sessions:
  • Delano: Wednesdays at 3pm-5pm EDT (same zoom link as lecture), or by appointment
  • Cheever: check his schedule
  • Ruether: by appointment Wednesdays 10am-12pm, Thursdays 3pm-5pm EDT (link)
  • Wizard sessions: Sunday 1-3pm EDT, Monday 7-9pm EDT (zoom link on moodle)

Learning Objectives and Outcomes

In this lecture, you will...

• read about the fundamentals of bitwise operators
• listen to a short lecture on using bitwise operators to perform different operations on bits (bitwise manipulation)

By the end of this lecture, you should be able to...

• use bitwise manipulation to set, clear, toggle, or test a bit, both on paper and programmatically

Bitwise Operators

In class so far we have discussed logical operators: logical AND (&&), logical OR (||), and logical NOT (!) and comparison operators (e.g. less than <, equal to (==)). These logical and comparison operators use the entire variable: 7 < 5 compares 7 and 5 and returns false. Bitwise operators are similar to logical operators, but function on individual bits. Let's illustrate this by an example:

$\ \ \ 010$ $\& 011$ ——— $\ \ \ 010$

In this case, an AND is performed for each bit individually. 0 AND 1 is 0, 1 AND 1 is 1, and 0 AND 0 is 0.

Bitwise operators have the following symbols: