Stack

struct Node {
    int key, maxcurr;
    Node *next;

    Node (int data): key (data), maxcurr (data), next (nullptr) {
    }
};

class Stiva {
public:
    Stiva (): peak (nullptr) {
    }
    void Push (int data) {
        Node *temp = new Node (data);
        if (!temp)
            return;

        if (isEmpty ())
            peak = temp;
        else {
            temp->next = peak;
            temp->maxcurr = max (temp->maxcurr, peak->maxcurr);
            peak = temp;
        }
    }
    void Pop () {
        if (isEmpty ())
            return;

        Node *temp = peak;
        peak = peak->next;
        delete temp;
    }
    bool isEmpty () const{
        return !peak;
    }
    int Top () const{
        if (!isEmpty ())
            return peak->key;
        else
            return - 1;
    }
    int Max () {
        if (!isEmpty ())
            return peak->maxcurr;
        else
            return - 1;
    }
    void Display () {
        if (!isEmpty ()) {
            stack <int> s;
            while (!isEmpty ())
                cout << Top () << " ", s.push (Top ()), Pop ();
            while (!s.empty ())
                Push (s.top ()), s.pop ();
        } else
            exit (EXIT_FAILURE);
    }
    ~Stiva () {
        while (!isEmpty ())
            Pop ();
    }

private:
    int key;
    Node *peak;
};