translate this ela

[angus@xxxxxxxxxxxx]

Can someone translate this ela in english ..the idea behind it.. I know it
is volatility but what to undesstand it..thanks

iNPUT: LENGTH (21), CONST(3.05);
vaR: SWITCH(1), TR(0), ARC(0), SAR(0),HISIC(0),LOSIC(0);
TR= VOLATILITY (LENGTH);
ARC= TR* CONST;
IF CURRENTbar = length then begin
hisic=c;
losic=c;
if h>= xaverage (h,length-1) [1] then begin
hisic= highest(c,length);
Sar=hisic-arc;
switch= 1;
end;
if l <= xaverage (l,length-1) [1] then begin
losic= lowest (c,length);
sar = losic +arc;
switch=0;
end;
end;