September Morn Update

Task/Fibonacci-sequence/BASIC/fibonacci-sequence-1.basic

@@ -1,14 +1,24 @@
-FUNCTION itFib (n)
-    n1 = 0
-    n2 = 1
-    FOR k = 1 TO ABS(n)
-        sum = n1 + n2
-        n1 = n2
-        n2 = sum
-    NEXT k
-    IF n < 0 THEN
-        itFib = n1 * ((-1) ^ ((-n) + 1))
-    ELSE
-        itFib = n1
-    END IF
-END FUNCTION
+# Basic-256 ver 1.1.4
+# iterative Fibonacci sequence
+# Matches sequence A000045 in the OEIS, https://oeis.org/A000045/list
+
+# Return the Nth Fibonacci number
+
+input "N = ",f
+limit = 500                        # set upper limit - can be changed, removed
+f = int(f)
+if f > limit then f = limit
+a = 0 : b = 1 : c = 0 : n = 0      # initial values
+
+
+while n < f
+    print n + chr(9) + c   # chr(9) = tab
+    a = b
+    b = c
+    c = a + b
+    n += 1
+
+end while
+
+print " "
+print n + chr(9) + c