Add iterative versions of tree traversals

trees/iterativetraversalsTree.cpp

@@ -0,0 +1,107 @@
+#include <bits/stdc++.h>
+using namespace std;
+struct Node
+{
+    int data;
+    Node *left;
+    Node *right;
+    Node(int data)
+    {
+        this->data = data;
+        this->left = this->right = nullptr;
+    }
+};
+
+void postOrder(Node *root)
+{
+    stack<Node *> st;
+    stack<int> out;
+    st.push(root);
+    while (!st.empty())
+    {
+        Node *tp = st.top();
+        st.pop();
+        out.push(tp->data);
+        if (tp->left)
+        {
+            st.push(tp->left);
+        }
+        if (tp->right)
+        {
+            st.push(tp->right);
+        }
+    }
+    while (!out.empty())
+    {
+        cout << out.top() << " ";
+        out.pop();
+    }
+    cout << endl;
+}
+
+void inOrder(Node *root)
+{
+    if (root == nullptr)
+        return;
+    stack<Node *> st;
+    Node *curr = root;
+    while (!st.empty() || curr != nullptr)
+    {
+        if (curr != nullptr)
+        {
+            st.push(curr);
+            curr = curr->left;
+        }
+        else
+        {
+            curr = st.top();
+            st.pop();
+            cout << curr->data << " ";
+            curr = curr->right;
+        }
+    }
+    cout << endl;
+}
+
+void preOrder(Node *root)
+{
+    if (root == nullptr)
+        return;
+    stack<Node *> st;
+    st.push(root);
+    while (!st.empty())
+    {
+        Node *curr = st.top();
+        st.pop();
+        cout << curr->data << " ";
+        if (curr->right)
+        {
+            st.push(curr->right);
+        }
+        if (curr->left)
+        {
+            st.push(curr->left);
+        }
+    }
+    cout << endl;
+}
+
+int main()
+{
+    Node *root = new Node(1);
+    root->left = new Node(2);
+    root->right = new Node(3);
+    root->left->left = new Node(4);
+    root->right->left = new Node(5);
+    root->right->right = new Node(6);
+    root->right->left->left = new Node(7);
+    root->right->left->right = new Node(8);
+    cout << "-------------Post Order------------\n";
+    postOrder(root);
+    cout << "-------------In Order------------\n";
+    inOrder(root);
+    cout << "-------------Pre Order------------\n";
+    preOrder(root);
+
+    return 0;
+}