CHAPTER 1 ■ ARDUINO BASICS
10
Listing 1-1. Recommended Code Structure
/*
* External Libraries
*/
#include
/*
* Constants & Variables
*/
char message[] = “Hello Internet of Things”; // Single line comment
/*
* Custom & Standard Functions
*/
void printMessage()
{
Serial.println(message);
}
void setup()
{
// Initialize serial port
Serial.begin(9600);
}
void loop()
{
printMessage();
delay(5000);
}
Listing 1-1 consists of three functions. It has two standard Arduino functions,
called setup() and loop() , which are automatically called by Arduino once the code
is uploaded. They therefore must be present for the code to run. The third is a custom
function called printMessage() that simply prints a message to the Serial Monitor
window shown in Figure  1-6 .
The setup() function is called only once. Initializations are done in this function
including serial monitor initialization using code Serial.begin(9600) . The loop()
function, as the name suggests, runs in a continuous loop. Any post-initialization
processing such as reading sensor data can be done in this function. The loop() function
calls printMessage() function and then waits 5,000 milliseconds before repeating.