Quick Index
What Is A Conditional Statement?


Recall the definition of condition.

A conditional statement is a conditional expression followed by a code block that executes if the expression is true. Similarly we may have a code block for false.

The next examples will explain.

Algorithmic Perspective


General
If the condition (expression) is true, then code "A" evaluates (runs).
If (CONDITION) {
	//CODE "A"
}
Specific Example
The condition is "a > b".

Thus, if the element "a" is greater than the element "b", then code "A" evaluates (runs).
If (a > b) {
	//CODE "A"
}


Everyday Conditions With Actions


When the condition is true we do a specified action.

Condition
Result
Action
(Code Block
When True)
Is the traffic signal green?
no
Stop
Am I thirsty?
true
Drink water
Is it cold out?
true
Put hat on
Is the price fair?
false
Do not buy

If True Code Block


If the condition expression evaluates to true, we do an action (code block).

Note we show print as the actions here to keep the example short. But in reality we can (and will) put all kinds of code into code these blocks.

Condition
Result
Code Block
Runs
When True
rec.isSquare()
true
Print "Square!"
rec1.canFitInsideOf(rec2)
false
-

If True Else False


The condition is either true else it is false. We can add a code block that will run for the else case.

Condition
Result
Code Block
Runs
When True
Code Block
Runs
When False
(Else Case)
rec.isSquare()
true
Print "Square!"
-
rec1.canFitInsideOf(rec2)
false
-
print "Nope won't fit"