B
--------------------|------------------
|                   |                 |
A             ------D-----         ---I---
             |      |    |        |       |
             C      E    G        H       L
                         |
                         F

void postorder(node)
{
   if(node=NULL)
      return;
   postorder(node.left);
   postorder(node.right);
   print(node);
}