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// from http://en.csharp-online.net/ECMA-334:_26.4_Implementation_example
// See also http://msdn.microsoft.com/msdnmag/issues/06/00/C20/default.aspx
using System;
using System.Collections;
using System.Collections.Generic;
class Tree<T> : IEnumerable<T>
{
private T value;
private Tree<T> left;
private Tree<T> right;
public Tree(T value, Tree<T> left, Tree<T> right) {
this.value = value;
this.left = left;
this.right = right;
}
// Returns the elements postorder
IEnumerator<T> IEnumerable<T>.GetEnumerator() {
if (left != null) foreach (T x in left) yield return x;
if (right != null) foreach (T x in right) yield return x;
yield return value;
}
IEnumerator IEnumerable.GetEnumerator() {
return ((IEnumerable<T>)this).GetEnumerator();
}
}
class Program
{
private static Tree<T> MakeTree<T>(params T[] items) {
return MakeTree(items, 0, items.Length - 1);
}
private static Tree<T> MakeTree<T>(T[] items, int left, int right) {
if (left > right) return null;
int i = (left + right) / 2;
return new Tree<T>(items[i],
MakeTree(items, left, i - 1),
MakeTree(items, i + 1, right));
}
public static void Main() {
{
Tree<int> t = MakeTree(1, 2, 3, 4, 5, 6, 7, 8, 9);
foreach (int i in t) Console.Write("{0} ", i);
Console.WriteLine();
}
{
Tree<string> t = MakeTree("Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun");
foreach (string s in t) Console.Write("{0} ", s);
Console.WriteLine();
}
}
}
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