template_class_"Stack".cpp

#include <iostream>
using namespace std;

template <typename T>
class Stack {
private:
    class Node {
    public:
        T data;
        Node* next;
        Node(const T& value, Node* n = nullptr) : data(value), next(n) {}
    };

    Node* head;
    size_t count;

public:
    Stack() : head(nullptr), count(0) {}
    ~Stack() { clear(); }

    void push(const T& value) {
        head = new Node(value, head);
        ++count;
    }

    void pop() {
        if (empty()) {
            cout << "Stack is empty!" << endl;
            return;
        }
        Node* temp = head;
        head = head->next;
        delete temp;
        --count;
    }

    T top() const {
        if (empty()) {
            throw runtime_error("Stack is empty!");
        }
        return head->data;
    }

    bool empty() const { return count == 0; }
    size_t size() const { return count; }

    void clear() {
        while (!empty()) {
            pop();
        }
    }

    void print() const {
        Node* temp = head;
        cout << "( ";
        while (temp) {
            cout << temp->data;
            if (temp->next) cout << ", ";
            temp = temp->next;
        }
        cout << " )" << endl;
    }
};

int main() {
    Stack<int> st;
    st.push(10);
    st.push(20);
    st.push(30);

    cout << "Stack: ";
    st.print();

    cout << "Top: " << st.top() << endl;
    cout << "Size: " << st.size() << endl;

    st.pop();
    cout << "After pop: ";
    st.print();

    return 0;
}