Re: If not Ada, what else...

[Waldek Hebisch <hebisch@math.uni.wroc.pl>]

Paul Rubin <no.email@nospam.invalid> wrote:
> Waldek Hebisch <hebisch@antispam.uni.wroc.pl> writes:
> >> > http://rosettacode.org/wiki/Hamming_numbers#Ada
> > AFAICS iterative version which uses array as a stream buffer
> > is about 20 lines long and quite easy to write. 
> 
> I'd be interested in seeing what that looks like.  There's a Java
> version on rosettacode that uses priority queues and is somewhat messy.

See below: computational part has 19 lines, the rest is driver
to print result and a boilerplate.  This version is limited to
Integer size, need different type to get bigger size.  Number
of artitmetic operations is linear with n0, so with appripriate
numeric type could go to quite large n0.

with Ada.Integer_Text_IO;    --  1  10.1.2, A.10 Context clause
procedure  hamming is
n0 : constant integer := 1_691;
buff : array(1..n0) of Integer;
procedure hamn(n : Integer) is
    cand : array(1..3) of Integer;
    ind : array(1..3) of Integer := (1, 1, 1);
    p : array(1..3) of Integer := (2, 3, 5);
    cmin : Integer;
    begin
        buff(1) := 1;
        for j in 1..3 loop cand(j) := p(j)*buff(ind(j)); end loop;
        cmin := cand(1);
        for j in 2..3 loop
                if cand(j) < cmin then cmin := cand(j); end if;
        end loop;
        buff(i) := cmin;
        for j in 1..3 loop
            if cand(j) = cmin then ind(j) := ind(j) + 1; end if;
        end loop;
    end loop;
end hamn;

begin
   hamn(n0);
   for i in 1..10 loop
       Ada.Integer_Text_IO.put(buff(i));
   end loop;
   Ada.Integer_Text_IO.put(buff(n0));
end hamming;

-- 
                              Waldek Hebisch
hebisch@math.uni.wroc.pl