YAPC::EU 2018 Glasgow Update!

Task/Fibonacci-sequence/Fortran/fibonacci-sequence-5.f

@@ -1,7 +1,20 @@
-program fibTest
-    use fibonacci
+    function fibI(n)
+        integer, intent(in) :: n
+        integer, parameter :: fib0 = 0, fib1 = 1
+        integer            :: fibI, back1, back2, i
 
-    do i = 0, 10
-        print *, fibr(i), fibi(i)
-    end do
-end program fibTest
+        select case (n)
+            case (:0);      fibI = fib0
+            case (1);       fibI = fib1
+
+            case default
+                fibI = fib1
+                back1 = fib0
+                do i = 2, n
+                    back2 = back1
+                    back1 = fibI
+                    fibI   = back1 + back2
+                end do
+         end select
+    end function fibI
+end module fibonacci