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Categories / C# / LINQ
 

Use select to retrieve all nodes in a Binary tree

using System; using System.Collections.Generic; using System.Linq; using System.Text; public class Tree<TreeNode> : IEnumerable<TreeNode> where TreeNode : IComparable<TreeNode> {     public Tree(TreeNode nodeValue) {         this.NodeData = nodeValue;         this.LeftTree = null;         this.RightTree = null;     }     public void Insert(TreeNode newItem) {         TreeNode currentNodeValue = this.NodeData;         if (currentNodeValue.CompareTo(newItem) > 0) {             if (this.LeftTree == null) {                 this.LeftTree = new Tree<TreeNode>(newItem);             } else {                 this.LeftTree.Insert(newItem);             }         } else {             if (this.RightTree == null) {                 this.RightTree = new Tree<TreeNode>(newItem);             } else {                 this.RightTree.Insert(newItem);             }         }     }     public void WalkTree() {         if (this.LeftTree != null) {             this.LeftTree.WalkTree();         }         Console.WriteLine(this.NodeData.ToString());         if (this.RightTree != null) {             this.RightTree.WalkTree();         }     }     public TreeNode NodeData { get; set; }     public Tree<TreeNode> LeftTree { get; set; }     public Tree<TreeNode> RightTree { get; set; }     IEnumerator<TreeNode> IEnumerable<TreeNode>.GetEnumerator() {         if (this.LeftTree != null) {             foreach (TreeNode item in this.LeftTree) {                 yield return item;             }         }         yield return this.NodeData;         if (this.RightTree != null) {             foreach (TreeNode item in this.RightTree) {                 yield return item;             }         }     }     System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator() {         throw new NotImplementedException();     } } class Employee : IComparable<Employee> {     public string FirstName { get; set; }     public string LastName { get; set; }     public string Department { get; set; }     public int Id { get; set; }     public override string ToString() {         return String.Format("Id: {0}, Name: {1} {2}, Dept: {3}", this.Id, this.FirstName, this.LastName, this.Department);     }     int IComparable<Employee>.CompareTo(Employee other) {         if (other == null)             return 1;         if (this.Id > other.Id)             return 1;         if (this.Id < other.Id)             return -1;         return 0;     } } class Program {     static void Main() {         Tree<Employee> empTree = new Tree<Employee>(new Employee { Id = 1, FirstName = "Janet", LastName = "Gates", Department = "IT" });         empTree.Insert(new Employee { Id = 2, FirstName = "O", LastName = "G", Department = "Marketing" });         empTree.Insert(new Employee { Id = 4, FirstName = "K", LastName = "H", Department = "IT" });         empTree.Insert(new Employee { Id = 6, FirstName = "L", LastName = "H", Department = "Sales" });         empTree.Insert(new Employee { Id = 3, FirstName = "E", LastName = "L", Department = "Sales" });         empTree.Insert(new Employee { Id = 5, FirstName = "D", LastName = "L", Department = "Marketing" });         var allEmployees = from e in empTree.ToList<Employee>()                            select e;         foreach (var emp in allEmployees)             Console.WriteLine(emp);     } }