RosettaCodeData/Task/Digital-root/Icon/digital-root.icon

procedure main(A)
    every m := n := integer(!A) do {
       ap := 0
       while (*n > 1) do (ap +:= 1, n := sumdigits(n))
       write(m," has additive persistence of ",ap," and digital root of ",n)
       }
end

procedure sumdigits(n)
    s := 0
    n ? while s +:= move(1)
    return s
end