Comparing Boolean Expressions

Comparing Boolean Expressions

Students will be able to...

• Apply De Morgan’s Laws to transform boolean expressions

• Identify and write logically equivalent boolean expressions

• Use truth tables to evaluate logical equivalence

• Compare object references and values using == and .equals()

• Determine when objects are the same or merely equivalent in attributes

Warm Up

Open Ended

Can two different expressions produce the same true/false result for all input values?

Warm Up

• Yes

• They can be logically equivalent, even if they may look different

Open Ended

Why might you want to simplify a boolean expression?

Warm Up

• Make code shorter

• Make code easier to read

Open Ended

What does it mean for two objects to be “equal”?

Warm Up

• Have the same values

• Are the exact same object

Open Ended

Using De Morgan’s Laws, what would be the equivalent of the expression below?

Open Ended

Using De Morgan’s Laws, what would be the equivalent of the expression below?

Now It's Your Turn!

• Head to CodeHS and access the Comparing Boolean Expressions (Part 2) modules. You will be completing:

  • Comparing Rectangles

  • Exploration: Comparing Strings

  • Determine Classmates

Wrap Up

Match

Match the following concepts

• Defines how we can negate AND and OR statements

• Used in logic for comparing Boolean Expressions

• Equality operator (==) compares the addresses in memory of two objects

• Checks if two objects have the same content or state (.equals)

• Two expressions that produce the same truth value for all inputs

DeMorgan's Laws

Truth Tables

Reference Equality

Value Equality

Logical Equivalence

• DeMorgan's Laws

• Truth Tables

• Reference Equality

• Value Equality

• Logical Equivalence

Open Ended

What do De Morgan’s Laws help you do when working with boolean expressions?

Wrap Up

• Help you rewrite expressions in different, equivalent ways

Open Ended

What is the difference between == and .equals() when comparing objects?

Wrap Up

• == checks if 2 variables point to the same object

• .equals() checks if they have the same content