Source code in the freebasic programming language

function leq( n as integer, m as integer ) as boolean
    if str(n)<=str(m) then return true else return false
end function

sub shellsort(s() as integer)
    dim as integer n = ubound(s)
    dim as integer i, inc = n
    dim as boolean done
 
    do
        inc\=2.2
        if inc = 0 then inc = 1
        do
            done = false
            for i = 0 to n - inc
                if leq(s(i+inc), s(i)) then
                    swap s(i), s(i + inc)
                    done = true
                end if
            next
        loop until done = 0
    loop until inc = 1
end sub

dim as integer n, i

input n

dim as integer s(0 to n-1)
for i = 0 to n-1
    s(i) = i+1
next i

shellsort(s())

print "[";
for i = 0 to n-1
    print s(i);
    if i
next i
print "]"