Question

i’m not really into basics algorithm programming, so here’s my problem. I want to create an algorithm which can populate a circular buffer but it have to start at the end of the buffer. I am trying to do it since many hours without succes, so i ask for your help.

I know the original algorithm which start by the begining of the buffer :
i = (i+1)%buffLen

But i want something that put something from buffLen-1 to 0, and when it reach 0, it start over from buffLen-1.

I know it can be done with a condition, but i’m sure there is a formula to do it faster and cleaner.

I need it to iterate infinitly through an array of objects by the end.

Sorry for my bad english.

Answer 1

Try

i = (i + buffLen - 1) % buffLen;

It isn’t going to be any more efficient than (or even as efficient as) an if..else construct, but it’s the analog to the one-line assignment for moving in the positive direction.