1. bfind.e / orphaned code?
I finally located this file on Jiri Babor's site. I really wish
that it was in the archive - Gabriel Boehme, Jiri Babor, Joe Otto,
and Luscious Hilley have not been active on the list for several
years. If Rob feels its appropriate, I'd like him to post it
in the archives:
global function bfind(object x, sequence s)
-- does a binary search on a sorted sequence
-- returns index location if found, 0 if not
-- assumes that sequence s has been sorted prior to this call
-- Gabriel Boehme's code
-- Earlier Joe Otto's routine is almost identical.
integer lo, hi, mid, c
lo = 1
hi = length(s)
while lo <= hi do
mid = floor((lo + hi) / 2)
c = compare(x, s[mid])
if c < 0 then -- x < s[mid]
hi = mid - 1
elsif c > 0 then -- x > s[mid]
lo = mid + 1
else -- x = s[mid]
return mid
end if
end while
return 0
end function
Luscious Hilley posted this to the list several years earlier:
----bfind.e
global function bfind(object this_in, sequence that)
integer min, max, gtlt, here
min = 0
max = length(that)
here = floor((max / 2) + .5)
while min != max do
gtlt = compare(this_in, that[here])
if gtlt = 0 then
return here
elsif gtlt = 1 then
min = here
here = floor(((min + max) / 2) + .5)
else
max = here
here = floor(((min + max) / 2) + .5)
end if
end while
return 0
end function
Ken Rhodes
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2. Re: bfind.e / orphaned code?
Kenneth Rhodes wrote:
> I finally located this file on Jiri Babor's site. I really wish
> that it was in the archive - Gabriel Boehme, Jiri Babor, Joe Otto,
> and Luscious Hilley have not been active on the list for several
> years. If Rob feels its appropriate, I'd like him to post it
> in the archives:
>
> global function bfind(object x, sequence s)
> -- does a binary search on a sorted sequence
> -- returns index location if found, 0 if not
> -- assumes that sequence s has been sorted prior to this call
> -- Gabriel Boehme's code
> -- Earlier Joe Otto's routine is almost identical.
> integer lo, hi, mid, c
> lo = 1
> hi = length(s)
>
> while lo <= hi do
> mid = floor((lo + hi) / 2)
> c = compare(x, s[mid])
> if c < 0 then -- x < s[mid]
> hi = mid - 1
> elsif c > 0 then -- x > s[mid]
> lo = mid + 1
> else -- x = s[mid]
> return mid
> end if
> end while
>
> return 0
> end function
>
> Luscious Hilley posted this to the list several years earlier:
>
> ----bfind.e
> global function bfind(object this_in, sequence that)
> integer min, max, gtlt, here
>
> min = 0
> max = length(that)
> here = floor((max / 2) + .5)
> while min != max do
> gtlt = compare(this_in, that[here])
> if gtlt = 0 then
> return here
> elsif gtlt = 1 then
> min = here
> here = floor(((min + max) / 2) + .5)
> else
> max = here
> here = floor(((min + max) / 2) + .5)
> end if
> end while
>
> return 0
> end function
I think whoever is working on the Euphoria Standard Library
should include this somewhere. I agree that a standard
binary search would be useful. Maybe I'll eventually add it
to euphoria\include somewhere.
Regards,
Rob Craig
Rapid Deployment Software
http://www.RapidEuphoria.com
