Algorithm 3 Binary Tree Traversal Recursive

Require: a binary tree $T$

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:PrintTree( $x.left$ )

7:PrintTree( $x.right$ )

8:end procedure

9:

10:PrintTree( $T.root$ )