Previous
Next

4. Deconstructing Blink

4.1. Comments

Let's take a look at the first part of the sketch. 

/*
  Blink

  Turns an LED on for one second, then off for one second, repeatedly.

  Most Arduinos have an on-board LED you can control. On the UNO, MEGA and ZERO
  it is attached to digital pin 13, on MKR1000 on pin 6. LED_BUILTIN is set to
  the correct LED pin independent of which board is used.
  If you want to know what pin the on-board LED is connected to on your Arduino
  model, check the Technical Specs of your board at:
  https://www.arduino.cc/en/Main/Products

  modified 8 May 2014
  by Scott Fitzgerald
  modified 2 Sep 2016
  by Arturo Guadalupi
  modified 8 Sep 2016
  by Colby Newman

  This example code is in the public domain.

  http://www.arduino.cc/en/Tutorial/Blink
*/
This is a comment, it is a piece of text that is completely ignored by the Arduino. Comments in code are used to write notes to anyone who might read your code.

We will use comments throughout our code examples to help explain what is going on. It is considered as a good practice to write comments in the programming world; it makes sharing code and remixing it a lot easier.

You can see if something is a comment because there is a 
/*
at the beginning and a 
*/
at the end.

One-line comments
// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
}

The first line starts with 

//
and is also a comment. This is used for short comments of one line.

Previous
Next