I know this is achievable with boost as per:

Using boost::accumulators, how can I reset a rolling window size, does it keep extra history?

But I really would like to avoid using boost. I have googled and not found any suitable or readable examples.

Basically I want to track the moving average of an ongoing stream of a stream of floating point numbers using the most recent 1000 numbers as a data sample.

What is the easiest way to achieve this?