Additive primes: Difference between revisions

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@@ Line 19: / Line 19: @@
 =={{header|ALGOL 68}}==
+{{libheader|ALGOL 68-primes}}
 <lang algol68>BEGIN # find additive primes - primes whose digit sum is also prime #
-    INT max prime = 499;
     # sieve the primes to max prime #
+    PR read "primes.incl.a68" PR
-    [ 1 : max prime ]BOOL prime;
-    prime[ 1 ] := FALSE; prime[ 2 ] := TRUE;
+    []BOOL prime = PRIMESIEVE 499;
-    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( max prime ) DO
-        IF prime[ i ] THEN FOR s FROM i * i BY i + i TO UPB prime DO prime[ s ] := FALSE OD FI
-    OD;
     # find the additive primes #
     INT additive count := 0;
-    FOR n TO max prime DO
+    FOR n TO UPB prime DO
         IF prime[ n ] THEN
             # have a prime #
@@ Line 47: / Line 42: @@
         FI
     OD;
-    print( ( newline, "Found ", whole( additive count, 0 ), " additive primes below ", whole( max prime + 1, 0 ), newline ) )
+    print( ( newline, "Found ", whole( additive count, 0 ), " additive primes below ", whole( UPB prime + 1, 0 ), newline ) )
 END</lang>
 {{out}}