Traversing a tree of objects in c#

BeefTurkey picture BeefTurkey · Jan 14, 2009 · Viewed 46.9k times · Source

I have a tree that consists of several objects, where each object has a name (string), id (int) and possibly an array of children that are of the same type. How do I go through the entire tree and print out all of the ids and names?

I'm new to programming and frankly, I'm having trouble wrapping my head around this because I don't know how many levels there are. Right now I'm using a foreach loop to fetch the parent objects directly below the root, but this means I cannot get the children.

Answer

ChrisW picture ChrisW · Jan 14, 2009

An algorithm which uses recursion goes like this:

printNode(Node node)
{
  printTitle(node.title)
  foreach (Node child in node.children)
  {
    printNode(child); //<-- recursive
  }
}

Here's a version which also keeps track of how deeply nested the recursion is (i.e. whether we're printing children of the root, grand-children, great-grand-children, etc.):

printRoot(Node node)
{
  printNode(node, 0);
}

printNode(Node node, int level)
{
  printTitle(node.title)
  foreach (Node child in node.children)
  {
    printNode(child, level + 1); //<-- recursive
  }
}