Talk:ALGOL 68-primes: Difference between revisions
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(Created a page with the source code for ALGOL 68-primes) |
(→Source code: Include 0 in the sieve) |
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OP PRIMESIEVE = ( INT n )[]BOOL: |
OP PRIMESIEVE = ( INT n )[]BOOL: |
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BEGIN |
BEGIN |
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[ |
[ 0 : n ]BOOL prime; |
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prime[ |
prime[ 0 ] := prime[ 1 ] := FALSE; |
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prime[ 2 ] := TRUE; |
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FOR i FROM 3 BY 2 TO UPB prime DO prime[ i ] := TRUE OD; |
FOR i FROM 3 BY 2 TO UPB prime DO prime[ i ] := TRUE OD; |
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FOR i FROM 4 BY 2 TO UPB prime DO prime[ i ] := FALSE OD; |
FOR i FROM 4 BY 2 TO UPB prime DO prime[ i ] := FALSE OD; |
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END; # PRIMESIEVE # |
END; # PRIMESIEVE # |
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# END primes.incl.a68 # |
# END primes.incl.a68 #</lang> |
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</lang> |
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Revision as of 16:54, 29 August 2021
Source code
<lang algol68># primes.incl.a68: prime related operators, procedure etc. #
# returns a sieve of primes up to n #
OP PRIMESIEVE = ( INT n )[]BOOL:
BEGIN
[ 0 : n ]BOOL prime;
prime[ 0 ] := prime[ 1 ] := FALSE;
prime[ 2 ] := TRUE;
FOR i FROM 3 BY 2 TO UPB prime DO prime[ i ] := TRUE OD;
FOR i FROM 4 BY 2 TO UPB prime DO prime[ i ] := FALSE OD;
FOR i FROM 3 BY 2 TO ENTIER sqrt( UPB prime ) DO
IF prime[ i ] THEN FOR s FROM i * i BY i + i TO UPB prime DO prime[ s ] := FALSE OD FI
OD;
prime
END; # PRIMESIEVE #
- END primes.incl.a68 #</lang>