Source code in the liberty programming language

wikiSample=1    'comment out for random array

data 6, 5, 3, 1, 8, 7, 2, 4
    itemCount = 20
if wikiSample then itemCount = 8
    dim A(itemCount)
    for i = 1 to itemCount
        A(i) = int(rnd(1) * 100)
        if wikiSample then read tmp: A(i)=tmp
    next i

    print "Before Sort"
    call printArray itemCount

    call heapSort itemCount

    print "After Sort"
    call printArray itemCount
end

'------------------------------------------
sub heapSort count
    call heapify count

    print "the heap"
    call printArray  count

    theEnd = count
    while theEnd > 1
        call swap theEnd, 1
        call siftDown 1, theEnd-1
        theEnd = theEnd - 1
    wend
end sub

sub heapify count
    start = int(count / 2)
    while start >= 1
         call siftDown start, count
         start = start - 1
    wend
end sub

sub siftDown start, theEnd
    root = start
    while root * 2 <= theEnd
        child = root * 2
        swap = root
        if A(swap) < A(child) then
            swap = child
        end if
        if child+1 <= theEnd  then
            if A(swap) < A(child+1) then
                swap = child + 1
            end if
        end if
        if swap <> root then
            call swap root, swap
            root = swap
        else
            exit sub
        end if
    wend
end sub

sub swap a,b
    tmp = A(a)
    A(a) = A(b)
    A(b) = tmp
end sub

'===========================================
sub printArray itemCount
    for i = 1 to itemCount
        print using("###", A(i));
    next i
    print
end sub