Honaker primes: Difference between revisions

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@@ Line 754: / Line 754: @@
 =={{header|Forth}}==
 {{works with|Gforth}}
-<syntaxhighlight lang="forth">: prime? ( n -- ? ) here + c@ 0= ;
+<syntaxhighlight lang="forth">5000000 constant limit
+create sieve limit allot
-: notprime! ( n -- ) here + 1 swap c! ;
-: prime_sieve { n -- }
+: prime? ( n -- ? ) sieve + c@ 0= ;
+: notprime! ( n -- ) sieve + 1 swap c! ;
-  here n erase
-notprime!
+: prime_sieve
-notprime!
-  n 4 > if
+  sieve limit erase
-    n 4 do i notprime! 2 +loop
-  then
   begin
-    dup dup * n <
+    dup dup * limit <
   while
     dup prime? if
-      n over dup * do
+      limit over dup * do
         i notprime!
       dup 2* +loop
@@ Line 781: / Line 779: @@
 /mod recurse + ;
-: next_prime ( u -- u )
+: next_odd_prime ( u -- u )
   begin
 + dup prime?
   until ;
 : next_honaker_prime ( u u -- u u )
   begin
-    swap next_prime swap 1+
+    swap next_odd_prime swap 1+
 dup digit_sum swap digit_sum =
   until ;
@@ Line 796: / Line 794: @@
 : main
-  5000000 prime_sieve
+  prime_sieve
   ." First 50 Honaker primes (index, prime):" cr
-0 0   \ prime prime-index honaker-index
+2 0   \ prime prime-index honaker-index
   begin
     dup 50 <