(* Compute a table of the first n primes numbers.  Print m
  numbers per line.  Use the method of the sieve of Erasthenes. *)

MODULE sieve;

FROM Terminal IMPORT WriteString, WriteLn;
FROM InOut    IMPORT WriteCard;

CONST size = 8190;
     m = 10;

VAR flags: ARRAY[0..size] OF BOOLEAN;
   i,prime,k,count: INTEGER;

BEGIN
 count := 0;
 FOR i := 0 TO size DO flags[i] := TRUE END;
 FOR i := 0 TO size DO
   IF flags[i] THEN
     prime := i+i+3;
     k := i+prime;
     WHILE k <= size DO
       flags[k] := FALSE;
       INC(k,prime)
     END;
     INC(count);
     WriteCard(prime,8);
     IF count MOD m = 0 THEN WriteLn END
   END
 END;
 WriteLn; WriteCard(count,0);
 WriteString(' primes'); WriteLn
END sieve.

You are viewing proxied material from gopher.floodgap.com. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.