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Task/Tree-traversal/Phix/tree-traversal.phix

@@ -0,0 +1,46 @@
+constant VALUE = 1, LEFT = 2, RIGHT = 3
+
+constant tree = {1, {2, {4, {7, 0, 0}, 0},
+                        {5, 0, 0}},
+                    {3, {6, {8, 0, 0},
+                            {9, 0, 0}},
+                        0}}
+
+procedure preorder(object tree)
+    if sequence(tree) then
+        printf(1,"%d ",{tree[VALUE]})
+        preorder(tree[LEFT])
+        preorder(tree[RIGHT])
+    end if
+end procedure
+
+procedure inorder(object tree)
+    if sequence(tree) then
+        inorder(tree[LEFT])
+        printf(1,"%d ",{tree[VALUE]})
+        inorder(tree[RIGHT])
+    end if
+end procedure
+
+procedure postorder(object tree)
+    if sequence(tree) then
+        postorder(tree[LEFT])
+        postorder(tree[RIGHT])
+        printf(1,"%d ",{tree[VALUE]})
+    end if
+end procedure
+
+procedure level_order(object tree, sequence more = {})
+    if sequence(tree) then
+        more &= {tree[LEFT],tree[RIGHT]}
+        printf(1,"%d ",{tree[VALUE]})
+    end if
+    if length(more) > 0 then
+        level_order(more[1],more[2..$])
+    end if
+end procedure
+
+puts(1,"\n preorder:    ")  preorder(tree)
+puts(1,"\n inorder:     ")  inorder(tree)
+puts(1,"\n postorder:   ")  postorder(tree)
+puts(1,"\n level-order: ")  level_order(tree)