SAA_Danny_zad2

#include <iostream>

using namespace std;

struct element
{
    int key;
    element*next;
}*f = NULL, *l = NULL;     // f - first ;   l - last

void push(int n)
{
    element *pointer = l;
    l = new element;
    l->key = n;
    l->next = NULL;
    if (pointer)
        pointer->next = l;
    else
        f = l;
}

int pop(int &n)
{
    if (f) {
        element *pointer = f;

        n = f->key;
        f = (f->next);

        delete pointer;

        if (f == NULL) {
            l = NULL;
        }

        return 1;
    }
    else
        return 0;
}

int del_k(int k)
{
    if (f) {
        element *pointer = f;
        element *helper = pointer;

        while (pointer->key != k && pointer->next) {     // dokato e razlichno ot k i ima sledvasht element
            helper = pointer;                            // predi da premine kum sledvashtiqt element, zapazva tekushtiqt v nov ukazatel
            pointer = pointer->next;                     // premestva se napred kum sledvashtiqt element
        }

        if (pointer->key == k) {

            if (f->key == k)          // ako purviqt element e raven na k
                f = f->next;          // purviqt element se premestva s edin element napred
            else
                helper->next = pointer->next;        // preskacha elementa

            delete pointer;                          // iztriva go
            return 1;
        }
        else {
            cout << "Nqmam k, nqa kvo da triq";

            return 0;
        }
    }
    else
        cout << "Prazna opashka !!";

    return 0;
}

void list() {
    if (f) {
        element *pointer = f;

        while (pointer) {
            cout << "\t" << pointer->key;
            pointer = pointer->next;
        }
    }
    else {
        cout << "\nEmpty";
    }
}

int main()
{
    int k, n = 0;
    do {
        cout << "\n Digit: ";
        cin >> k;
        push(k);
        n++;
    } while (k > 0);

    cout << "\n Opashkata:  ";
    list();
    cout << endl;

    cout << "\n Opashkata sled iztritiq posleden:  ";

    while (pop(k)) {
        if (n != 1) {
            cout << "\t" << k;
            push(k);
            n--;
        }
        else
            pop(k);
    }

    cout << endl << endl;

    return 0;
}