Using Boolean Expressions and Relational Operators

As you saw in the algorithm section, an algorithm is comprised of sequential steps, conditionals, and iterative processes. Sequential steps are those done in order. Conditionals allow the program to behave in different ways based on decisions. Iterative processes repeat series of steps.

In this tutorial we will focus on Boolean expressions, which are critical to conditionals and iterative processes.

Boolean Expressions

Recall that a boolean variable is assigned either true or false. A Boolean expression is any expression that can be evaluated to a boolean value, true or false. They are comprised of relationship operators and logic operators.

Relationship Operators

The relationship operators compare values and evaluate to either true or false. They are as follows:

Operator	Name	Description	Example
`>`	greater than	evaluates to `true` if the value on the left is greater than the value on the right and `false` otherwise.	`3 > 5` evaluates to `false` `5 > 3` evaluates to `true` `5 > 5` evaluates to `false` since the values are equal
`<`	less than	evaluates to `true` if the value on the left is less than the value on the right and `false` otherwise.	`3 < 5` evaluates to `true` `5 < 3` evaluates to `false` `5 < 5` evaluates to `false` since the values are equal
`>=`	greater than or equal to	evaluates to `true` if the value on the left is greater than or equal to the value on the right and `false` otherwise.	`3 >= 5` evaluates to `false` `5 >= 3` evaluates to `true` `5 >= 5` evaluates to `true` since the values are equal
`<=`	less than or equal to	evaluates to `true` if the value on the left is less than or equal to the value on the right and `false` otherwise.	`3 <= 5` evaluates to `true` `5 <= 3` evaluates to `false` `5 <= 5` evaluates to `true` since the values are equal
`==`	equal to	evaluates to `true` if the values are equal to each other and `false` otherwise.	`3 == 5` evaluates to `false` `5 == 5` evaluates to `true` since the values are equal
`!=`	not equal to	evaluates to `true` if the values are not equal to each other and `false` otherwise.	`3 != 5` evaluates to `true` `5 != 5` evaluates to `false`

Your Turn

Predict the result of the program code.
Run the code to check your predictions.

Try these out in the Java Playground. Take a few minutes to change the values and see the new results.

Your Turn

Predict the result of the program code.
Run the code to check your predictions.
Write a few more statements that use arthimetic expressions and relational operators.
Predict the result of these statements.
Run the code to check your predictions.

The values being compared could be variables, expressions, or values. In these examples, we have integrated variables and expressions. Take a few minutes to change the values and see the new results.

Resources

Practice: Using Relational Operators