Algorithm 5 Tree Traversal Recursive

Require: a tree $T$ using left-child, right-sibling representation

Ensure: print all keys appearing in $T$

1:procedure PrintTree( $x$ )

2:if $x == NIL$ then

3:return

4:end if

5:print $x.key$

6: $y = x.left$ - $child$

7:while $y \ne NIL$ do

8:PrintTree( $y$ )

9: $y = y.right$ - $sibling$

10:end while

11:end procedure

12:

13:PrintTree( $T.root$ )