os-prakt

// #include <windows.h>
#include <iostream>
#include <bits/stdc++.h>
#define MEMORY_SIZE 1024
using namespace std;

struct Queue{
    int front, rear, capacity, temp;
    int* queue;
    Queue(int c)
    {
        front = rear = 0;
        capacity = c;
        queue = new int;
    }

    ~Queue() { delete[] queue; }


    bool empty(){
        return front == rear;
    }

    void empty_or_not(){
        if (empty()){
            cout << "Queue is empty" << endl;
        }

        else{
            cout << "Queue is not empty"<<endl;
        }
    }

    void Enqueue(int data)
    {
        if (capacity == rear) {
            printf("\nQueue is full\n");
            return;
        }

        else {

            /* links to material: https://tdoc.ru/c/cpp-sources/win32/virtualalloc-i-virtualfree.html
            and https://learn.microsoft.com/en-us/windows/win32/Memory/reserving-and-committing-memory

            все это должно добавлять в массив объекты размером в 20Кб (не пробовал, т.к. онлайн комплиятор не поддерживает windows.
            а устанавливать расширение для MS VS не хочется (долго) )

            cout << "Enter your element (only int value): "
            cin >> queue[rear];
            VirtualAlloc(NULL, 20*MEMORY_SIZE, MEM_RESERVE|MEM_COMMIT, PAGE_EXECUTE_READWRITE);
            */
            queue[rear] = data;
            rear++;
            cout << "\n" << data << " was added in queue" << endl;
        }


        return;
    }

    void Dequeue()
    {

        if (empty()) {
            printf("\nQueue is empty\n");
            return;
        }
        else{

            temp = queue[front];
            for (int i = 0; i < rear - 1; i++) {
                queue[i] = queue[i + 1];
            }
            rear--;
        }

        cout << temp << " was deleted from queue"<< endl;
        return;
    }


    void view_head()
    {
        if (empty()) {
            printf("\nQueue is Empty\n");
            return;
        }
        else{
            printf("Head Element is: %d ", queue[front]);

        }
        return;
    }


    void show_queue(){
        int i;
        if (empty()){
            printf("\nQueue is empty\n");
            return;
        }
        else{
            cout << endl;
            cout << "Queue elements: ";
            for (i = front; i < rear; i++) {
                printf("%d ", queue[i]);

             }
            return;
        }
    }

    void swap_head(){
        if (empty()){
            printf("\nQueue is empty\n");
            return;
        }

        else{
            temp = queue[front];
            //cout << "\n" <<temp << endl;
            queue[front] = queue[rear-1];
            //cout << "\n" <<queue[front] << endl;
            queue[rear-1] = temp;
        }
    }
};


int main(){

    Queue q(5);

    q.empty_or_not();
    cout << "\nAfter enquing elements:" << endl;
    q.Enqueue(1);
    q.empty_or_not();
    q.Enqueue(2);
    q.Enqueue(3);
    cout << "\nBefore swapping head to tail:" << endl;
    q.show_queue();

    q.swap_head();
    cout << "\nAfter swapping head to tail:" << endl;
    q.show_queue();
    cout << endl;
    q.view_head();
    return 0;
}