Expert: Narendra - 9/23/2005

Question
In an interview i was asked about use of structure padding,i told processing speed gets increased,then they asked that how is it going to increase ?.
I want to know the answer for it.

thanks,
vara

Answer
What you told is correct.
But that is the byproduct.

Actually structure padding is done to do memory alignment.
As you know the size of pointer is 4 bytes.
So, if everything is organized by a multiple of 4, then it will be easier and faster to calculate the addresses and processing them.

But, this is not true always. One of the places is structures where different sized variables are clubbed.
So, if you want to make things faster, then make them align to 4 byte boundaries and for that you need padding.

-Narendra