#include <iostream>
/*
struct Node {
    int el;
    Node* ptrNext;
};

//void insertAtBeginning(Node* start, int n) {
void insertAtBeginning(Node*& start, int n) {
    Node* ptrTemp = new Node;
    ptrTemp->el = n;
    ptrTemp->ptrNext = start;
    start=ptrTemp;
}

//void print(Node*& start) {
void print(Node* start) {
    while (start) {
        std::cout << start-> el << " ";
        start=start->ptrNext;
    }
    std::cout << std::endl;
}
*/
/*
void print(Node*& start) {
//void print(Node* start) {
    Node* temp = start;
    while (temp) {
        std::cout << temp-> el << " ";
        temp=temp->ptrNext;
    }
    std::cout << std::endl;
}
*/

int main() {
    int a = 10;
    int b = 20;
    int* p_a = &a;
    int** p_p_a = &p_a;
    std::cout << "a " << &a << " " << a << std::endl;
    std::cout << "b " << &b << " " << b << std::endl;
    std::cout << "p_a " << &p_a << " " << p_a << " " << *p_a << std::endl;
    std::cout << "p_p_a " << &p_p_a << " " << p_p_a << " " << *p_p_a  << " " << **p_p_a << std::endl;
    std::cout << "------------------------" << std::endl;
    /*
    //The nullptr keyword represents a null pointer value.
    Node* ptrStart = nullptr;
    insertAtBeginning(ptrStart, 3);
    insertAtBeginning(ptrStart, 2);
    insertAtBeginning(ptrStart, 1);
    print(ptrStart);
    print(ptrStart);

    while (ptrStart) {
        Node* ptrTemp = ptrStart->ptrNext;
        delete ptrStart;
        ptrStart=ptrTemp;
    }
    */
    return 0;
}