Date:         Fri, 26 Sep 2008 06:32:34 -0700
Reply-To:     Chris Jones <chrisj75@GMAIL.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Chris Jones <chrisj75@GMAIL.COM>
Organization: http://groups.google.com
Subject:      Re: hi all,
              I to find prime number using Macro program and using base SAS.
Comments: To: sas-l@uga.edu
Content-Type: text/plain; charset=ISO-8859-1

On 26 Sep, 14:15, Dirk Nachbar <dirk...@googlemail.com> wrote:
> On Sep 26, 4:55 am, Satya <kondal4u...@gmail.com> wrote:
>
> > hi all
> >  I to find prime number from 1 to 20  using Macro program and using
> > base SAS.
> > I tried but that code is some how big .
> > Bye.
>
> hi
>
> here is ths solution
>
> option mprint;
> %macro prime(n);
> data prime;
> do i=1 to &n;
>     prime=1;
>     do j=2 to ceil(i/2);
>         if mod(i,j)=0 then prime=0;
>     end;
>     if prime=1 then output;
> end;
> run;
> %mend;
> %prime(20);

Alternative solution to find all primes up to a certain maximum:

%LET MAX =
500000 ;

data
primes ;
  do number = 3 to
&MAX ;
    /* does it divide by 2?
*/
    if mod(number,2) ^= 0 then
do ;
      /* loop through odd numbers >= 3
*/
      testnum =
3 ;
      limit =
number ;
      do while (limit >
testnum) ;
        if mod(number,testnum) = 0 then
do ;
          limit = 0 ; /* force exit of while loop
*/

end ;
        else
do ;
          limit = ceil(number/
testnum) ;
          testnum + 2 ; /* only need to check odd numbers
*/

end ;

end ;

      if limit ^= 0 then output ; /* if limit ^= 0 we successfully
exited loop */
    end ; /* mod 2
*/
  end ; /* do
*/
run ;