#include <iostream>

using namespace std;
class Deque{
public:

    Deque(int size){
        deque = new int[size];
        first=last=(deque+size/2);
        _size=size;
    }

    void unshift(int value){

        if(first!=last+1){
            if(count==0){
                count++;
                *first = value;
            }
            else{
                count++;
                first--;

                if(first==deque-1)
                    first=deque+_size-1;

                *first=value;
            }
        }
        else cout<<"Queue is full"<<endl;
    }
    int shift(){
        if(count==0){
            return 0;
        }
        else{
            count--;
            value = *first;

            first++;

            if(first==deque+_size)
            first=deque;

            return value;
        }
    }

    void push(int value){
        if(last+1!=first)
            if(count==0){
                count++;
                *last = value;
            }
            else{
                last++;
                count++;

                if(last==deque+_size)
                    last=deque;

                *last=value;
            }
        else cout<<"Queue is full"<<endl;
    }

    int pop(){
        if(count==0){
            return 0;
        }
        else{
            count--;
            value = *last;
            last--;

            if(last==deque-1)
                last=deque+_size-1;

            return value;
        }
    }

    void showDeque(){
        int* i = first;

        if(count == 0){
            cout<<"pust";
        }
        else
            for(int f = 0; f<count;f++){
                cout<<*i<<' ';
                i++;
                if(i==deque+_size)
                    i=deque;
            }
    }

    ~Deque(){
        delete deque;
    }
private:
    int _size;
    int* deque;
    int value;
    int* first = 0;
    int* last = 0;
    int count = 0;
};
int main()
{
     Deque d(10);
    int x;
    int value;
    int position;

    cout << "1 dlya vstaski v nachalo" << endl
    << "2 dlya vzyatiya s nachala" << endl
    << "3 dlya vstavki v konec" << endl
    << "4 dlya vzatia s konca" << endl
    << "0 dlya vihoda" << endl;

    while (x !=0){

        cout<<endl<<"Vvedi nomer ";
        cin>>x;
        switch(x){
            case 1: cout << "vvedi chislo ";
                    cin >> value;
                    d.unshift(value); break;
            case 2: cout<<d.shift()<<endl;break;

            case 3: cout << "vvedi chislo ";
                    cin >> value;
                    d.push(value); break;

            case 4: cout<<d.pop()<<endl;break;


        }
        cout << "Spisok seychas: "; d.showDeque();
    }

return 0;
}