Representations of Trees

Many different representations of trees are possible:

• Binary tree: contents and left and right links.
  • arithmetic expressions

    

  • cons as a binary tree node, with first and rest treated equally as binary links
• First-child/next-sibling: contents, first child, next sibling.

• Linked list: the first element contains the contents, the rest are a linked list of children.

• Implicit: a node may contain only the contents; the children can be generated from the contents or from the location of the parent.