Well formatted Arduino code in one click

Warning, the title of this post is a little bit misleading. It isn’t just one-click to get cleanly formatted code, it’s actually two.

There are two things seasoned programmers will tell new programmers, that they don’t understand (at first):

  1. Always comment your code
  2. Properly indent code

The problem?  As a new programmer, you might not know how to do #2 until you get some experience.

How indenting helps

The reason you indent code is to make it easier for a reader to understand the code’s flow.  A compiler (well except in Python) doesn’t care if two lines line up or not.  The recent issues around Apple’s “goto fail;” are a great example of how indentation is meaningless to a C compiler.

Looking at the following example, it is pretty clear (to humans) that line 1 is a decision point and lines 2-3 belong with line.

if (sensorValue > 100) {
   warningFlag = true;

Most modern code development environments try to help with proper formatting, and the Arduino IDE is no different. However, the IDE isn’t proactive as some of the more professional-focused tools. For this reason, one of the least used, yet very powerful features of the IDE is hidden in the Tools menu.

The magic command won’t remove extra spaces between lines, but it’ll reformat some pretty messy things.

Arduino Autoformat Example with CTRL-T

A little help with CTRL-T

The image above shows how it takes the non-formatted code and turns it into something far, far more readable.

One Caution

The only thing i don’t like is how it handles “else” blocks.  I prefer to write my else blocks like this:

if (something) {
   // Do It!
} else {
  // Don't!

and it’ll format them into this:

if (something) {
   // Do It!
else {
  // Don't!

Not a huge difference and both are readable. For me, it is just personal preference to keep the braces (or brackets?) along with the else.

Where is it at?

How do you access this wonderful command?  It’s “hidden” in the tools menu.



Arduino Tools Window

The keyboard shortcut is Ctrl-T (Win/Linux) or Cmd-T (Mac) and it is under the Tools Menu.  Before I compile code, I almost always hit the keyboard shortcut to see the result.

Since I focused on the Arduino IDE, let me know if other environments offer this kind of clean up in the comments.

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5 thoughts on “Well formatted Arduino code in one click

  1. Thank you for pointing it out, I didn’t know the Arduino IDA had it.
    I don’t know which types of IDE you mean, but the bigger ones like Visual Studio, Eclipse or Netbeans do that.
    I work a lot with Eclipse and there you can set formatting as a “save action”, this means, your code is automatically formatted while saving. Also, you can set the formatting behaviour, so like you said the if-else thing (to be on separate lines or not), if there should be blanks beneath parentheses
    (like func( param ) or func(param) or func (param)) and whatnot else. You can also make missing comments on classes, public constants and functions cause a warning!