added code of finding the middle of linked list in a single traversal

Cpp/middle_linked_list.cpp

@@ -0,0 +1,79 @@
+#include <iostream>
+using namespace std;
+class ListNode {
+public:
+    int val;
+    ListNode *next;
+
+    ListNode(int x) : val(x), next(nullptr) {}
+};
+
+class LinkedList {
+public:
+    ListNode *head;
+
+    LinkedList() : head(nullptr) {}
+
+    void append(int value) {
+        if (!head) {
+            head = new ListNode(value);
+        } else {
+            ListNode *current = head;
+            while (current->next) {
+                current = current->next;
+            }
+            current->next = new ListNode(value);
+        }
+    }
+
+    int findMiddle() {
+        if (!head) {
+            return -1;  // Or any other value indicating an empty list
+        }
+
+        ListNode *slow = head;
+        ListNode *fast = head;
+
+        while (fast && fast->next) {
+            slow = slow->next;
+            fast = fast->next->next;
+        }
+
+        return slow->val;
+    }
+
+    // Destructor to free allocated memory
+    ~LinkedList() {
+        while (head) {
+            ListNode *temp = head;
+            head = head->next;
+            delete temp;
+        }
+    }
+};
+
+// Function to input values from the user
+void inputLinkedList(LinkedList &linkedList) {
+    int n, value;
+    cout<< "Enter the number of elements in the linked list: ";
+    cin>> n;
+
+    cout << "Enter the values of the linked list: ";
+    for (int i = 0; i < n; ++i) {
+        cin >> value;
+        linkedList.append(value);
+    }
+}
+
+// Example Usage:
+int main() {
+    LinkedList linkedList;
+
+    // Input values from the user
+    inputLinkedList(linkedList);
+
+    int middleValue = linkedList.findMiddle();
+    cout << "Middle value of the linked list: " << middleValue << endl;
+
+    return 0;
+}