Stack.cpp

#include <iostream>
using namespace std;

template <typename T>
struct Node{
    T data;
    Node *next;

    Node(T val){
        data = val;
        next = nullptr;
    }
};

template <typename T>
class Stack{
private:
    Node<T> *top;
    int size;

public:
    Stack(){
        size = 0;
        top = nullptr;
    }

    bool isEmpty(){
        return top == nullptr;
    }

    void push(T val){
        Node<T> *newNode = new Node(val);
        newNode->next = top;
        top = newNode;
        size++;
    }

    T pop(){
        Node<T> *delptr = top;
        if(isEmpty()){
            throw runtime_error("Stack is empty!");
        }
        top = top->next;
        delete delptr;
        size--;
    };

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

    void display(){
        if(isEmpty()){
            cout << "Stack is empty!" << endl;
            return;
        }
        Node<T> *current = top;
        while(current != nullptr){
            cout << current->data << endl;
            current = current->next;
        }
        cout << "------------" << endl;
    }

    bool search(T val){
        if(isEmpty()){
            cout << "Stack is empty!" << endl;
            return false;
        }
        Node<T> *current = top;
        while(current != nullptr){
            if (current->data == val){
                return true;
            }
            else{
                current = current->next;
            }
        }
        return false;
    }

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

    int getSize(){
        return size;
    }

};

int main() {
    Stack<int> st;

    // Push some values
    st.push(10);
    st.push(20);
    st.push(30);
    cout << "After pushing 10, 20, 30:" << endl;
    st.display();

    // Peek at the top value
    cout << "Peek: ";
    cout << st.peek() << endl;

    // Search for a value
    cout << "Search for 20: " << (st.search(20) ? "Found" : "Not found") << endl;
    cout << "Search for 100: " << (st.search(100) ? "Found" : "Not found") << endl;

    // Pop a value
    cout << "Popping top value..." << endl;
    st.pop();
    st.display();

    // Get current size
    cout << "Current stack size: " << st.getSize() << endl;

    // Clear the stack
    cout << "Clearing stack..." << endl;
    st.clear();
    st.display();

    // Final size
    cout << "Stack size after clearing: " << st.getSize() << endl;

    return 0;
}