Rosetta Code

Quadrat special primes: Difference between revisions

Page Discussion

Quadrat special primes (view source)

Revision as of 16:27, 29 August 2021

428 bytes removed ,  2 years ago
→‎{{header|ALGOL 68}}: Use ALGOL 68-primes
(clarify task)
(→‎{{header|ALGOL 68}}: Use ALGOL 68-primes)
Line 9:
=={{header|ALGOL 68}}==
{{Trans|ALGOL W}}
{{libheader|ALGOL 68-primes}}
<lang algol68>BEGIN # find some primes where the gap between the current prime and the next is a square #
# reurns a sieve of primes up to n #
PROC eratosthenes = ( INT n )[]BOOL:
BEGIN
[ 1 : n ]BOOL p;
p[ 1 ] := FALSE; p[ 2 ] := TRUE;
FOR i FROM 3 BY 2 TO n DO p[ i ] := TRUE OD;
FOR i FROM 4 BY 2 TO n DO p[ i ] := FALSE OD;
FOR i FROM 3 BY 2 TO ENTIER sqrt( n ) DO
IF p[ i ] THEN FOR s FROM i * i BY i + i TO n DO p[ s ] := FALSE OD FI
OD;
p
END # eratosthenes # ;
# an array of squares #
PROC get squares = ( INT n )[]INT:
Line 30 ⟶ 19:
END # get squares # ;
INT max number = 16000;
PR read "primes.incl.a68" PR
[]BOOL prime = eratosthenes(PRIMESIEVE max number );
[]INT square = get squares( max number );
INT p count, this prime, next prime;
Tigerofdarkness
3,037

edits

Retrieved from "https://rosettacode.org/wiki/Special:MobileDiff/310149"