'iterative binary search example

define size = 0, search = 0, flag = 0, value = 0
define middle = 0, low = 0, high = 0

dim list[2, 3, 5, 6, 8, 10, 11, 15, 19, 20]

arraysize size, list

let value = 4
gosub binarysearch

let value = 8
gosub binarysearch

let value = 20
gosub binarysearch

end

sub binarysearch

	let search = 1
	let middle = 0
	let low = 0
	let high = size

	do

		if low <= high then

    			let middle = int((high + low ) / 2)
			let flag = 1

     			 if value < list[middle] then

				let high = middle - 1
				let flag = 0

			endif

      			if value > list[middle] then

				let low = middle + 1
				let flag = 0

      			endif

			if flag = 1 then

				let search = 0

    			endif

		endif

	loop low <= high and search = 1

	if search = 1 then

		let middle = 0

	endif

	if middle < 1 then

		print "not found"

	endif

	if middle >= 1 then

		print "found at index ", middle

	endif

return