Root

Definition

The root is the chosen starting node of a rooted tree.

Example:

    A
   / \
  B   C

Here A is the root.

Root = starting node of a tree hierarchy.

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Root Gives Direction To A Tree

A plain tree does not always have an inherent top or bottom.

When we choose a root, the tree becomes organized around that node.

Example:

Root: A

A
|-- B
+-- C

Now B and C are below A.

The root gives the tree an orientation.

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Root Has No Parent

In a rooted tree, the root has no parent.

Example:

    A
   / \
  B   C

A is the root.

B and C may have A as parent.

But A has no parent inside this tree.

The root is where parent-child structure begins.

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Different Root, Different View

The same tree can be viewed differently if a different root is chosen.

Example:

A -- B -- C

If A is root:

A
`-- B
    `-- C

If B is root:

B
|-- A
+-- C

Root choice affects the hierarchy we see.

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Why Roots Matter

Roots matter when a structure needs a starting point.

Examples:

• file system folder trees
• decision trees
• parse trees
• search trees
• dependency explanations

A root turns a branching structure into an organized hierarchy.

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Final Summary

• The root is the chosen starting node of a rooted tree.
• A root gives direction to tree structure.
• The root has no parent in the tree.
• The same tree can be rooted in different ways.
• Roots are useful when a hierarchy needs a starting point.