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If Statement (Conditional Statement)

The If statement is the most basic of all programming control structures. It allows you to make something happen or not depending on whether a given condition is true or not. It looks like this: 

if (someCondition) {
   // do stuff if the condition is true
}

There is a common variation called if-else that looks like this: 

if (someCondition) {
   // do stuff if the condition is true
} else {
   // do stuff if the condition is false
}

There's also the else-if, where you can check a second condition if the first is false: 

if (someCondition) {
   // do stuff if the condition is true
} else if (anotherCondition) {
   // do stuff only if the first condition is false
   // and the second condition is true
}

You'll use if statements all the time. The example below turns on an LED on pin 13 (the built-in LED on many Arduino boards) if the value read on an analog input goes above a certain threshold.

Circuit

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image developed using Fritzing. For more circuit examples, see the Fritzing project page

Schematic:

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Code

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