A-M baby

Task/Mutual-recursion/Fortran/mutual-recursion-1.f

@@ -0,0 +1,24 @@
+module MutualRec
+  implicit none
+contains
+  pure recursive function m(n) result(r)
+    integer :: r
+    integer, intent(in) :: n
+    if ( n == 0 ) then
+       r = 0
+       return
+    end if
+    r = n - f(m(n-1))
+  end function m
+
+  pure recursive function f(n) result(r)
+    integer :: r
+    integer, intent(in) :: n
+    if ( n == 0 ) then
+       r = 1
+       return
+    end if
+    r = n - m(f(n-1))
+  end function f
+
+end module

Task/Mutual-recursion/Fortran/mutual-recursion-2.f

@@ -0,0 +1,17 @@
+program testmutrec
+  use MutualRec
+  implicit none
+
+  integer :: i
+  integer, dimension(20) :: a = (/ (i, i=0,19) /), b = (/ (i, i=0,19) /)
+  integer, dimension(20) :: ra, rb
+
+  forall(i=1:20)
+     ra(i) = m(a(i))
+     rb(i) = f(b(i))
+  end forall
+
+  write(*,'(20I3)') rb
+  write(*,'(20I3)') ra
+
+end program testmutrec