Updating with actual code

L13_AlltraversalsCpp

@@ -14,48 +14,62 @@
 class Solution {
 
 public:
-    vector<int> postorderTraversal(TreeNode* root) {
-        stack<pair<TreeNode*,int>> st; 
-        st.push({root, 1}); 
-        vector<int> pre, in, post;
-        if(root == NULL) return post;
-
-        while(!st.empty()) {
-            auto it = st.top(); 
-            st.pop(); 
-
-            // this is part of pre
-            // increment 1 to 2 
-            // push the left side of the tree
-            if(it.second == 1) {
-                pre.push_back(it.first->val); 
-                it.second++; 
-                st.push(it); 
-
-                if(it.first->left != NULL) {
-                    st.push({it.first->left, 1}); 
-                }
+    void traversal(node *root)
+    {
+        if (!root)
+            return;
+
+        vector<int> PreOrder, InOrder, PostOrder;
+
+        stack<pair<node *, int>> S;
+
+        S.push({root, 1});
+
+        while (!S.empty())
+        {
+            if (S.top().second == 1)
+            {
+                PreOrder.push_back(S.top().first->data);
+                S.top().second++;
+
+                if (S.top().first->left)
+                    S.push({S.top().first->left, 1});
             }
 
-            // this is a part of in 
-            // increment 2 to 3 
-            // push right 
-            else if(it.second == 2) {
-                in.push_back(it.first->val); 
-                it.second++; 
-                st.push(it); 
-
-                if(it.first->right != NULL) {
-                    st.push({it.first->right, 1}); 
-                }
+            else if (S.top().second == 2)
+            {
+                InOrder.push_back(S.top().first->data);
+                S.top().second++;
+
+                if (S.top().first->right)
+                    S.push({S.top().first->right, 1});
             }
-            // don't push it back again 
-            else {
-                post.push_back(it.first->val); 
+
+            else
+            {
+                PostOrder.push_back(S.top().first->data);
+                S.pop();
             }
-        } 
+        }
+
+        cout << "Pre Order : ";
+
+        for (int it : PreOrder)
+            cout << it << " ";
+
+        cout << "\n";
+
+        cout << "In Order : ";
+
+        for (int it : InOrder)
+            cout << it << " ";
+
+        cout << "\n";
+
+        cout << "Post Order : ";
 
-        return post; 
+        for (int it : PostOrder)
+            cout << it << " ";
     }
 };