Add Forth

1 files changed, 37 insertions, 0 deletions

diff --git a/gcd.fs b/gcd.fs
new file mode 100644
index 0000000..1baeda0
--- /dev/null
+++ b/gcd.fs
@@ -0,0 +1,37 @@
+: gcd ( a b -- d )
+  2dup > if swap endif
+  over mod
+  dup 0 <> if recurse else drop endif
+  ;
+
+: gcdn ( a1 a2 .. an n -- d )
+  dup 1 >
+  if
+    1 - rot rot
+    gcd
+    swap
+    recurse
+  else
+    drop
+  endif
+  ;
+
+
+\ This is gforth-specific.
+\ Usage:
+\ # gforth ./gcd.fs 11 22 33 121
+\ 11 
+
+: main
+  0 >r
+  begin
+  next-arg 2dup 0 0 d<> while
+  s>unumber? if drop else abort endif
+  r> 1 + >r
+  repeat
+  2drop
+  r> gcdn . cr
+  ;
+
+main bye
+