calculating the average of the kast x days close

[tj.dale]

Hi,

I am trying to measure the average of the last x days close for creating a backtesting strategy. There does not appear to be a function to allow this.

Anybody have one. Something along the lines of :-

average(price,x) where price is OHLC, and x is the number of bars into the past to measure the average over.....

Any ideas here would be appreciated.

many thanks in advance

TJ