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JavaScript Introduction to Programming Objects and Arrays Arrays

Posted by Nicholas Chan
Nicholas Chan
1,281 Points

What is the difference between i+=1 and i++

I found out that i++ is an increment of i by whereas in this chapter, the teacher uses i+=1 instead. May I know what is the difference between two? Thank you very much.

4 Answers

Laura Cressman
Laura Cressman
12,548 Points
Laura Cressman
Laura Cressman
12,548 Points

There is no difference, both do the same thing.

The i++ is shorthand for i += 1.

You can use other numbers for +=, like "i += 2" if you wanted to print only even numbers, for example, but i++ only increments by one. We also have i--, which is the same as i -= 1.

Does that make sense?

Russell Beye
Russell Beye
3,367 Points
Russell Beye
Russell Beye
3,367 Points

Let's explore this side-by-side:

i++: Here, the value of i is returned first, then it is incremented. In a common example, if you set i = 1, and x = i++, you should find that x = 1. This is called post increment.

++i: In this case, i is first incremented and then returned. Again, i = 1, x = ++i, you'll find x = 2. This is called pre increment.

In an overwhelming amount of cases, this won't be a problem as it won't affect your loops. It's nice to know what is out there though. I would prefer to use i++ because it maintains the form of a proper expression; the target operand is on the left side of the expression.

You can learn more: http://stackoverflow.com/questions/24853/what-is-the-difference-between-i-and-i

Nicholas Chan
Nicholas Chan
1,281 Points
Nicholas Chan
Nicholas Chan
1,281 Points

Thanks Laura for the answer!

Russell Beye
Russell Beye
3,367 Points
Russell Beye
Russell Beye
3,367 Points

Don't forget that we also have ++i, which can have different side effects than i++. ;)

Nicholas Chan
Nicholas Chan
1,281 Points

Hi Russell, can you tell me more about ++1? Like what does this formula returns?