Piprimes: Difference between revisions

Content added Content deleted

Inline

@@ Line 13: / Line 13: @@
 =={{header|ALGOL 68}}==
+{{libheader|ALGOL 68-primes}}
 <lang algol68>BEGIN # Show some values of pi(n) - the number of priems <= n  #
-    # reurns a sieve of primes up to n #
-    PROC prime sieve = ( 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 # prime sieve # ;
     # show pi(n) for n up to 21 #
-    INT max number = 100; # guess of how large the primes we need are #
+    INT max prime = 100; # guess of how large the primes we need are #
-    INT max pi     = 21;
+    INT max pi    = 21;
+    PR read "primes.incl.a68" PR
-    []BOOL prime   = prime sieve( max number );
+    []BOOL prime = PRIMESIEVE max prime;
     INT pi        := 0;
-    FOR i TO max number
+    FOR i TO UPB prime
     WHILE IF prime[ i ] THEN pi +:= 1 FI;
           pi <= max pi
@@ Line 50: / Line 40: @@
 20 21 21 21 21 21 21
 </pre>
 =={{header|Arturo}}==