Arrow symbol in for loop

Question

On a few occasions I have seen an arrow like symbol combination being used in a for loop like such:

for(int i = 100; i --> 0;) {
    System.out.println(i);
}

What's happening here?

That's the "goes to" operator. https://stackoverflow.com/q/1642028/1288 — Bill the Lizard, Jan 01 '19 at 00:28
`IntStream.range(0, 100).forEachOrdered(i -> System.out.println(99 - i));` — Elliott Frisch, Jan 01 '19 at 00:29
Your version is a very odd way to write `for (int i = 99; i >= 0; i--)` — Elliott Frisch, Jan 01 '19 at 00:30
I must warn: while this 'operator' is easy to find with a simple search query on Google, such code might be not immediately clear to the reader. I strongly suggest using a "normal" for loop, like the one Elliot Frisch mentioned. — MC Emperor, Jan 01 '19 at 00:40
Welcome. I suggest that you take the [tour] of the Help Center, and in particular read the section on [ask]. It's expected that you should do your own research before you post a new question. — Tedinoz, Jan 01 '19 at 00:41

score 7 · Accepted Answer · answered Jan 01 '19 at 00:24

7

This is not an arrow, but a decrement operator followed by a greater than sign.

What the compiler sees is a less clear version of (i--) > 0

answered Jan 01 '19 at 00:24

Joe C

Ahh. Gotcha. It was confusing at first because I've seen more than one person do it in their code. Thanks for the clarification! – MP1 Jan 01 '19 at 00:26
4

*"I've seen more than one person do it in their code."* - Tell them to stop it! – Stephen C Jan 01 '19 at 00:39
1

@MP1 If you found this helpful, don't forget to upvote and accept this answer. (And I agree with Stephen, as you have shown that is unclear.) – Joe C Jan 01 '19 at 13:38

Ousmane D. · Answer 2 · 2019-01-01T01:36:50.937

1

It's the post-decrement operator along with the greater than symbol combined which is confusing and unreadable.

it's the same as writing:

for(int i = 100; (i--) > 0;) { ... }

i.e. i --> 0 is essentially (i--) > 0.

edited Jan 01 '19 at 01:36

answered Jan 01 '19 at 00:25

Ousmane D.

2

Actually, because it's post decrement, it's more like: is `(i > 0)` followed by `i = i - 1;` – dave Jan 01 '19 at 00:28

2 Answers2