The code between the is called the body of the function: what the function does.
The text before and after the name specify its return type and parameters: these will be explained later. The first line provides information about the function, like its name, 'setup'. For example, here's the definition of the setup() function from the Blink example: There's more information in the Variables tutorial.Ī function (otherwise known as a procedure or sub-routine) is a named piece of code that can be used from elsewhere in a sketch. For example, you could store the value read from an input into a variable. Often, however, the value of a variable will change while the sketch runs.
The advantage of using a variable is that it's easier to move the LED to a different pin: you only need to edit the one line that assigns the initial value to the variable. In this case, the person writing the program could have chosen not to bother creating the ledPin variable and instead have simply written 13 everywhere they needed to specify a pin number. Every time the name ledPin appears in the code, its value will be retrieved. It's being used to indicate which Arduino pin the LED is connected to. For example, the line from the Blink sketch above declares a variable with the name ledPin, the type int, and an initial value of 13. The message 'LED connected to digital pin 13' is a comment.Ī variable is a place for storing a piece of data.
