How do I write a PCF for price as a % of max high ar max low. The point is to have a column that shows where price is today compared to a recent high or low. Good way to find double tops or bottoms.

Price as a percent of the highest high over the most recent 50 bars.

100 * C / MAXH50

Price as a percent of the lowest low over the most recent 30 bars.

100 * C / MINL30

You can get an idea of where price is relative to both the highs and lows over a period using a stochastic. Where price is relative to the most recent 40 versus both the high and low (with 100 being at the high and 0 being at the low) could be written as follows.

STOC40

Stochastic