Dirkster.TreeLib 1.1.0

TreeLib

This project produces a <a href="https://docs.microsoft.com/en-us/dotnet/standard/net-standard">.Net Standard</a> Library with Generic methods to traverse k-nary trees in different orders of traversal.

Implementing something as complicated as a Post-Order traversal algorithm requires just:

• a project reference,
• a <a href="https://msdn.microsoft.com/en-us/library/bb308959.aspx">LINQ</a> statement to find each set of children in the tree,
• and a simple for each loop to implement the operation on each tree node:

Console.WriteLine("(Depth First) PostOrder Tree Traversal V3");
items = TreeLib.Depthfirst.Traverse.PostOrder(root, i => i.Children);

foreach (var item in items)
{
  Console.WriteLine(item.GetPath());
}

This pattern leads to a clear-cut separation of:

• the traversal algorithm and
• the operations performed on each tree node (e.g.: Console.WriteLine(item.GetPath());).

The project in this repository contains a demo console project to demo its usage in more detail.

Supported Generic Traversal Methods

Breadth First

Level Order

See TreeLib.BreadthFirst.Traverse.LevelOrder implementation for:

• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/BreadthFirst/TraverseLevelOrder.cs">Trees with 1 root node</a> (expects 1 <T> root item as parameter)
• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/BreadthFirst/TraverseLevelOrderEnumerableRoot.cs">Trees with multiple root nodes</a> (expects an IEnumerable<T> root item as parameter)
• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/BreadthFirst/LevelOrder.cs">Generic Level-Order</a> function and <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/TreeLibNugetDemo/Program.cs">DemoDirectoryTreeTraversal</a>

Depth First

PreOrder

See TreeLib.BreadthFirst.Traverse.PreOrder implementation for:

• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/Depthfirst/TraversePreorder.cs">Trees with 1 root node</a> (expects 1 <T> root item as parameter)
• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/Depthfirst/TraversePreorderEnumerableRoot.cs">Trees with multiple root nodes</a> (expects IEnumerable<T> root as parameter)
• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/Depthfirst/PreOrder.cs">Generic Pre-Order</a> function and <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/TreeLibNugetDemo/Program.cs">DemoDirectoryTreeTraversal</a>

Postorder

See TreeLib.BreadthFirst.Traverse.Postorder implementation for:

• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/Depthfirst/TraversePostOrder.cs">Trees with 1 root node</a> (expects 1 <T> root item as parameter)
• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/Depthfirst/TraversePostOrderEnumerableRoot.cs">Trees with multiple root nodes</a> (expects IEnumerable<T> root item as parameter)
• <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/Shared/Depthfirst/PostOrder.cs">Generic Post-Order</a> function and <a href="https://github.com/Dirkster99/TreeLib/blob/master/source/TreeLibNugetDemo/Program.cs">DemoDirectoryTreeTraversal</a>

Tip

• Read about <a href="http://www.codeducky.org/easy-tree-and-linked-list-traversal-in-c/">Generic Tree and Linked List Traversal in C#</a> to understand the usefulness of Generic traversal methods.

• Watch the <a href="https://www.youtube.com/watch?v=gm8DUJJhmY4">Binary tree traversal: Preorder, Inorder, Postorder</a> video to better understand what is what (and why these Traversal Order Names make some sense):

• Look into data structure books online or offline by Robert Sedgewick and Kevin Wayne, if you still need more background on tree structures