display all paths from root to leaf node - recursively

Author: NirmalSilwal

CodingBlocks Training/Day21/rootToLeafTraversalTree.java

@@ -0,0 +1,82 @@
+package Lecture21;
+
+import Lecture21.binaryTree.Node;
+
+public class rootToLeafTraversalTree {
+
+	public static void main(String[] args) {
+
+		binaryTree btree = new binaryTree();
+		System.out.println("\n----------------------------------------\n");
+		btree.display();
+		System.out.println("\n------- root to leaf traversal -----------\n");
+		rootToLeaf(btree.root);
+	}
+
+	public static void rootToLeaf(Node node) {
+		String initialOutput = "";
+		rootToLeaf(node, initialOutput);
+	}
+
+	private static void rootToLeaf(Node node, String currentPath) {
+		if (node == null) {
+			return;
+		}
+		if (node.left == null && node.right == null) {
+			currentPath = currentPath + node.data;
+			System.out.println(currentPath);
+			return;
+		}
+
+		rootToLeaf(node.left, currentPath + node.data + " => ");
+		rootToLeaf(node.right, currentPath + node.data + " => ");
+
+	}
+}
+
+
+
+/* output:
+Enter data for root node: 50
+Do you have left child for 50 -> true/false: true
+Enter data for left child of 50: 25
+Do you have left child for 25 -> true/false: true
+Enter data for left child of 25: 12
+Do you have left child for 12 -> true/false: false
+Do you have right child for 12 -> true/false: false
+Do you have right child for 25 -> true/false: true
+Enter data for right child of: 25: 68
+Do you have left child for 68 -> true/false: false
+Do you have right child for 68 -> true/false: false
+Do you have right child for 50 -> true/false: true
+Enter data for right child of: 50: 75
+Do you have left child for 75 -> true/false: true
+Enter data for left child of 75: 39
+Do you have left child for 39 -> true/false: false
+Do you have right child for 39 -> true/false: false
+Do you have right child for 75 -> true/false: true
+Enter data for right child of: 75: 49
+Do you have left child for 49 -> true/false: false
+Do you have right child for 49 -> true/false: true
+Enter data for right child of: 49: 63
+Do you have left child for 63 -> true/false: false
+Do you have right child for 63 -> true/false: false
+
+----------------------------------------
+
+25 => 50 <= 75
+12 => 25 <= 68
+END => 12 <= END
+END => 68 <= END
+39 => 75 <= 49
+END => 39 <= END
+END => 49 <= 63
+END => 63 <= END
+
+------- root to leaf traversal -----------
+
+50 => 25 => 12
+50 => 25 => 68
+50 => 75 => 39
+50 => 75 => 49 => 63
+*/