From a4c29a4b5922a58415ea39af4ea0b5d6b6432458 Mon Sep 17 00:00:00 2001
From: Ritish Sehgal <59483233+apex-blaze@users.noreply.github.com>
Date: Fri, 9 Apr 2021 18:22:11 +0530
Subject: [PATCH] Added 3 basic traversals in Binary Trees (#144)

* added max subarray sum

* added pre,in,post traversals

* Update pre-in-post-traversal.cpp

formatted the output

* Update pre-in-post-traversal.cpp

formatted output

Co-authored-by: Arsenic <54987647+Arsenic-ATG@users.noreply.github.com>
---
 trees/README.md                          |  5 ++
 trees/c-or-cpp/pre-in-post-traversal.cpp | 76 ++++++++++++++++++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 trees/README.md
 create mode 100644 trees/c-or-cpp/pre-in-post-traversal.cpp

diff --git a/trees/README.md b/trees/README.md
new file mode 100644
index 00000000..49a1f944
--- /dev/null
+++ b/trees/README.md
@@ -0,0 +1,5 @@
+# Trees
+
+### C or C++
+
+1. [Pre, In & Post Order Traversals](c-or-cpp/pre-in-post-traversal.cpp)
diff --git a/trees/c-or-cpp/pre-in-post-traversal.cpp b/trees/c-or-cpp/pre-in-post-traversal.cpp
new file mode 100644
index 00000000..1d272b93
--- /dev/null
+++ b/trees/c-or-cpp/pre-in-post-traversal.cpp
@@ -0,0 +1,76 @@
+#include<iostream>
+#define endl "\n"
+using namespace std;
+
+
+// Basic Structure of a Tree
+struct Node{
+    int data;
+    struct Node *left;
+    struct Node *right;
+
+    Node(int val){
+        data = val;
+        left = NULL;
+        right = NULL;
+    }
+};
+
+/* Pre, In and Post order Traversal of a Binary Tree using recusrion */
+/* Complexity for each Traversal : O(n) */
+
+// LST -> Left SubTree   RST -> Right SubTree
+
+// Pre-Order goes like :-   Root, LST, RST (Recursively)
+void pre_order(struct Node* root){
+    if(root == NULL)
+      return;
+    cout<<root->data<<" ";
+    pre_order(root->left);
+    pre_order(root->right);
+}
+
+// In-Order goes like :-   LST, Root, RST (Recursively)
+void in_order(struct Node* root){
+    if(root == NULL)
+      return;
+    in_order(root->left);
+    cout<<root->data<<" ";
+    in_order(root->right);
+}
+
+// Pre-Order goes like :-  LST, RST, Root (Recursively)
+void post_order(struct Node* root){
+    if(root == NULL)
+      return;
+    post_order(root->left);
+    post_order(root->right);
+    cout<<root->data<<" ";
+}
+
+
+int main(){
+    Node* root = new Node(1);
+    root->left = new Node(2);
+    root->right = new Node(3);
+    root->left->left = new Node(4);
+    root->left->right = new Node(5);
+    root->right->right = new Node(7);
+
+    /*                       
+                    1
+                   / \
+                  2   3
+                 / \   \
+                4   5   7    
+        Expected-> pre-order :  1,2,4,5,3,7
+                   in-order  :  4,2,5,1,3,7
+                   post-order:  4,5,2,7,3,1
+    
+    */
+   cout<<"pre-order : "; pre_order(root); cout<<endl;
+   cout<<"in-order : "; in_order(root); cout<<endl;
+   cout<<"post-order : "; post_order(root); cout<<endl;
+
+    return 0;
+}