// recursivePreOrderTraverse traverse by pre-order recursively.
recursivePreOrderTraverse traverse by pre-order recursively.
// recursivePreOrderTraverse traverse by pre - order recursively .
func recursivePreOrderTraverse(n *Node) {
	if n != nil {
		fmt.Printf("%d\n", n.Key)
		recursivePreOrderTraverse(n.Left)
		recursivePreOrderTraverse(n.Right)
	}
}
func recursivePreOrderTraverse ( n * Node ) { if n != nil { fmt . Printf ( " \n " , n . Key ) recursivePreOrderTraverse ( n . Left ) recursivePreOrderTraverse ( n . Right ) } }
recursivePreOrderTraverse traverse by pre-order recursively.
recursivePreOrderTraverse traverse by pre - order recursively .