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> One approach that would need to be updated each week would be to
> define a 2 dimensional array. One dim being the weekly high, the
> other dim being the weekly closing date. ( Or may this two single
> dimension arrays.
All you need is two 52-long single-dimension arrays, to hold the
weekly high and low for each of the last 52 weeks. Then you can do
something like this:
vars: Wk(0), ThisWkHigh(0), ThisWkLow(99999999), High52(0), Low52(0);
arrays: WkHigh[53](0), WkLow[53](0);
if DayOfWeek(Date) < DayOfWeek(Date[1]) then begin { New week }
WkHigh[53] = ThisWkHigh;
WkLow[53] = ThisWkLow;
High52 = 0;
Low52 = 999999999;
for Wk = 1 to 52 begin
WkHigh[Wk] = WkHigh[Wk+1];
WkLow[Wk] = WkLow[Wk+1];
High52 = MaxList(High52, WkHigh[Wk]);
Low52 = MinList(Low52, WkLow[Wk]);
end;
ThisWkHigh = 0;
ThisWkLow = 99999999;
end;
ThisWkHigh = MaxList(H, ThisWkHigh);
ThisWkLow = MinList(L, ThisWkLow);
(Not tested, but it should be close)
As soon as you hit a bar in a new week, the code in the if gets
executed. It stores the previous week's H/L in the "53rd week" slot
(so it can cheat and compute the 52-week H/L while it's in the loop),
and then shifts all the previous weekly highs/lows back one week.
Then the last two lines record the H/L for the new week.
(It would be fancier to use a "circular buffer" for the H/L's, so you
wouldn't have to shift the data. But that's more confusing to code,
and the shift action only happens once a week, so who cares if it's a
little less efficient? Besides, you need to scan through the arrays
to find the H/L anyway.)
High52 and Low52 are your 52-week H & L.
Gary
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