/// Stack using Linked List /// we are using single Linked List and manage using head pointer not tail #include using namespace std; /*****************************/ // Template T is generic class which work for any datatype. template class Node { public: T data; Node *next; Node(T data) : data(data), next(NULL) {} }; //-------------------------------- template class Stack { Node *head; int size{0}; public: Stack() { head = NULL; size = 0; } //-------------------------------- getSize() - O(1) int getSize() { return size; } //---------------------------------- isEmpty() - O(1) bool isEmpty() { if (head == NULL) { return true; } return false; } //---------------------------------- push() - O(1) void push(int data) { Node *temp = new Node(data); temp->next = head; head = temp; size++; } //--------------------------------- pop() - O(1) void pop() { if (head == NULL) { cout << "==============" << endl; cout << "STACK EMPTY!!!" << endl; cout << "==============" << endl; return; } Node *temp = head; head = head->next; /// free node - isolation step temp->next = NULL; delete temp; size--; } //---------------------------------- top_element() - O(1) T top() { if (head == NULL) { cout << "==============" << endl; cout << "STACK EMPTY!!!" << endl; cout << "==============" << endl; return 0; } return head->data; } }; /*****************************/ int main() { Stack s; s.push(10); s.push(20); s.push(30); s.push(40); s.push(50); cout << s.getSize() << endl; cout << s.top() << endl; s.pop(); }

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