An if expression is a conditional that executes a body of code only when a specified Boolean value returns true.
Assume we had a Boolean variable called raining:
We can use an if expression to evaluate the value of raining to determine whether or not we execute some code:
- The expression starts with the keyword,
if. - A pair of parentheses contains a condition (
raining) that evaluates to eithertrueorfalse. - Following the condition is a pair of brackets
{and}that holds a block of code.
The code contained within the code block of the if expression will only execute if the condition is true; otherwise, that code block will be ignored.
When we run the program above, we get the following output:
The value of raining inside of the if expression is true; therefore, the instruction println("Bring an umbrella.") gets executed.
Instructions
Your neighbor keeps forgetting what day the garbage gets picked up. You decide to create a small program to remind them when to take their garbage out.
Create an if expression that checks if the value of isTuesday is true.
Inside the if expression, create a println() statement that outputs "Take out the trash."