Fix PrintAsTree operation

Author: Marusyk

samples/BinaryTreeConsole/Program.cs

@@ -9,6 +9,8 @@ private static void Main()
         {
             var binaryTree = new BinaryTree<int> { 8, 5, 12, 3, 7, 10, 15 };
 
+            binaryTree.PrintAsTree();
+
             Console.Write("Pre-order : ");
             binaryTree.TraversalStrategy = new PreOrderTraversal<int>();
             binaryTree.PrintToConsole();

src/BinaryTree/BinaryTree.cs

@@ -7,7 +7,7 @@ namespace BinaryTree
     public class BinaryTree<T> : ICollection<T> where T : IComparable<T>
     {
         private ITraversalStrategy<T> _traversalStrategy;
-        public BinaryTreeNode<T> _head;
+        private BinaryTreeNode<T> _head;
 
         public BinaryTree(ITraversalStrategy<T> traversalStrategy)
         {
@@ -34,6 +34,8 @@ public BinaryTree()
         {
         }
 
+        public BinaryTreeNode<T> Head => _head;
+
         public ITraversalStrategy<T> TraversalStrategy
         {
             get => _traversalStrategy ?? (_traversalStrategy = new InOrderTraversal<T>());

src/BinaryTree/EnumerableExtensions.cs

@@ -7,28 +7,28 @@ public static class EnumerableExtensions
     {
         public static void PrintToConsole<T>(this IEnumerable<T> source)
         {
-            if (source is BinaryTree<int>)
+            foreach (var item in source)
             {
-                BinaryTree<int> binaryTree = (BinaryTree<int>)source;
-                binaryTree.Print();
+                Console.Write($"{item} ");
             }
-            else
+        }
+
+        public static void PrintAsTree<T>(this IEnumerable<T> source)
+        {
+            if (source is BinaryTree<int> binaryTree)
             {
-                foreach (var item in source)
-                {
-                    Console.Write($"{item} ");
-                }
+                binaryTree.Print();
+                return;
             }
-
-            
+            throw new NotSupportedException("Support only for numbers");
         }
 
-        public static void Print(this BinaryTree<int> root, string textFormat = "0", int spacing = 1, int topMargin = 2, int leftMargin = 2)
+        private static void Print(this BinaryTree<int> root, string textFormat = "0", int spacing = 1, int topMargin = 2, int leftMargin = 2)
         {
             if (root == null) return;
             int rootTop = Console.CursorTop + topMargin;
             var last = new List<NodeInfo>();
-            var next = root._head;
+            var next = root.Head;
             for (int level = 0; next != null; level++)
             {
                 var item = new NodeInfo { Node = next, Text = next.Value.ToString(textFormat) };