Day 5: Lesson 01 – Arduino/C Functions and Serial Input

A critical part of learning any language is the ability to break apart your program into “subroutines”.

In C, and therefore Arduino, we use Functions.

We have already used a few – Setup and Loop are functions, and PrintLn is a function (method) of the Serial object.

Creating Arduino/C Functions

Functions are built in the form:

ReturnType functionName(InputType variableName)
{
 // do stuff
 return "data";
}
Eg. 
String hey(String name)
{
 Serial.println("Hey " + name);
 return "Done!";
}

Don’t Repeat Yourself

One of the best habits to get into when coding is to create small, reusable elements, rather than rely on copy and paste.

It’s easier to understand when reading back (for others, as well as yourself at a later date), and easier to debug.

As a rule of thumb, each function should exist for just one purpose.

Serial Input Demonstration

To demonstrate how functions work, let’s create a sketch that asks the user to input something into the serial monitor input box.

Did you notice the serial monitor allows input as well as showing output?

Serial Input Code