Can you explain me (int i=0; i<8; i++, data>>=1)?

Question

I know that the for loop needs to be in the form of for (initialization; condition; increment) In this case there is a fourth part, do you know what it does?

There are only 3 parts. There are only two `;` in your code. Maybe you mistake the comma for a semicolon. — M.M, Apr 01 '16 at 03:37
the C comma operator *is* somewhat rarely seen. If we don't already have a suitable answer around here, it wouldn't hurt to write one :) — hobbs, Apr 01 '16 at 03:39
I did not do any mistake. I tested the code and it works. Hence this for loop it is correct. Another for loop that is used in the code is for (int b=0; b<4; b++, freq>>=8). I am confused — Andreas, Apr 01 '16 at 03:40
The mistake is that you said there are 4 parts but actually there are only 3 parts. The parts are separated by the `;` symbol — M.M, Apr 01 '16 at 03:42
@GisMofx It is valid syntax, what part of it are you not sure about — M.M, Apr 01 '16 at 03:43
@M.M I just looked it up. That bitwise assignment. Never used it before. Andreas it appears it's doing i++ and data = data >>1 on each loop iteration. — GisMofx, Apr 01 '16 at 03:50
Also, @Andreas your answer is here: http://stackoverflow.com/questions/1232176/how-to-put-two-increment-statements-in-a-c-for-loop — GisMofx, Apr 01 '16 at 03:54
@GisMOfx and M.M Thank you for your help. I really appreciate it — Andreas, Apr 01 '16 at 03:58

score 0 · Accepted Answer · answered Apr 01 '16 at 03:43

There is no fourth part. The third part contains the comma operator which simply allows you to put various statements together as if one where you can't use {}. Pretty much the only time I've ever used them is like this (and while ) where you have a single place where you want to do more than one thing.

In this case, the last part of the loop is both incrementing i (i++) and shifting data right once (dividing by 2) at the end of each iteration

Can you explain me (int i=0; i<8; i++, data>>=1)?

1 Answers1