How do I print out a tree structure?

Question

I\'m trying to improve performance in our app. I\'ve got performance information in the form of a tree of calls, with the following node class:

public class         


        

Answer 1

With Recursion

You'll need to keep track of an indentation string that's modified as you go deeper into the tree. To avoid adding extra | characters, you'll also need to know whether the Node is the last child in that set.

public static void PrintTree(Node tree, String indent, Bool last)
{
    Console.Write(indent + "+- " + tree.Name);
    indent += last ? "   " : "|  ";

    for (int i = 0; i < tree.Children.Count; i++)
    {
        PrintTree(tree.Children[i], indent, i == tree.Children.Count - 1);
    }
}

When called like this:

PrintTree(node, "", true)

It will output text like this:

+- root
   +- branch-A
   |  +- sibling-X
   |  |  +- grandchild-A
   |  |  +- grandchild-B
   |  +- sibling-Y
   |  |  +- grandchild-C
   |  |  +- grandchild-D
   |  +- sibling-Z
   |     +- grandchild-E
   |     +- grandchild-F
   +- branch-B
      +- sibling-J
      +- sibling-K

Without Recursion

If you happen to have a very deep tree and your call stack size is limited, you can instead do a static, non-recursive tree traversal to output the same result:

public static void PrintTree(Node tree)
{
    List firstStack = new List();
    firstStack.Add(tree);

    List> childListStack = new List>();
    childListStack.Add(firstStack);

    while (childListStack.Count > 0)
    {
        List childStack = childListStack[childListStack.Count - 1];

        if (childStack.Count == 0)
        {
            childListStack.RemoveAt(childListStack.Count - 1);
        }
        else
        {
            tree = childStack[0];
            childStack.RemoveAt(0);

            string indent = "";
            for (int i = 0; i < childListStack.Count - 1; i++)
            {
                indent += (childListStack[i].Count > 0) ? "|  " : "   ";
            }

            Console.WriteLine(indent + "+- " + tree.Name);

            if (tree.Children.Count > 0)
            {
                childListStack.Add(new List(tree.Children));
            }
        }
    }
}