Coding an indicator?

Hi,

Can anyone help with this simple coding indicator for MT4?

study(title=“Candle Size”, shorttitle=“Candle Size”)
open_pos = open1
close_pos = close
1

// Body size as a percentage of the total candle
diff = abs(close_pos-open_pos)
plot(diff)

The difference can be plotted either in percentage or pips value.