double ended queue

#include <iostream>
#include <stdlib.h>
#define maks 5

using namespace std;

struct data
{
    int numb[maks];
    int front;
    int rear;
}Data;

void inisialisasi()
{
    Data.front=-1;
    Data.rear=maks;
}

bool isFull()
{
    return Data.front==Data.rear-1;
}

bool isEmpty()
{
    return Data.front==-1 && Data.rear==maks;
}

void enqueFront()
{
    if (isFull())
    {
        cout << "Error: Data sudah penuh!" << endl;
    }
    else
    {
        Data.front++;
        cout << "Masukkan angka = ";
        cin >> Data.numb[Data.front];
    }
}

void enqueRear()
{
    if (isFull())
    {
        cout << "Error: Data sudah penuh!" << endl;
    }
    else
    {
        Data.rear--;
        cout << "Masukkan angka = ";
        cin >> Data.numb[Data.rear];
    }
}

void dequeFront()
{
    if(isEmpty())
    {
        cout << "Error: Data masih kosong!" << endl;
    }
    else
    {
        for (int i=0;i<Data.front;i++)
        {
            Data.numb[i]=Data.numb[i+1];
        }
        Data.front--;
    }
}

void dequeRear()
{
    if(isEmpty())
    {
        cout << "Error: Data masih kosong!" << endl;
    }
    else
    {
        for (int i=maks-1;i>Data.rear;i--)
        {
            Data.numb[i]=Data.numb[i-1];
        }
        Data.rear++;
    }
}

void show()
{
    if (isEmpty())
    {
        cout << "Error: Data masih kosong!" << endl;
    }
    else
    {
        for(int i=0;i<=Data.front;i++)
        {
            cout  << Data.numb[i] << " ->";
        }
        cout << " ";
        for (int i=Data.rear;i<maks;i++)
        {
            cout << " <- "  << Data.numb[i];
        }
    }
}

int main()
{
    int pil;
    inisialisasi();
    do
    {
        system("cls");
        cout << "1. Enque front\n";
        cout << "2. Enque rear\n";
        cout << "3. Deque front\n";
        cout << "4. Deque rear\n";
        cout << "5. show data\n";
        cout << "Input : ";
        cin>> pil;

        switch(pil)
        {
        case 1:
            {
                enqueFront();
                system("pause");
                break;
            }
        case 2:
            {
                enqueRear();
                system("pause");
                break;
            }
        case 3:
            {
                dequeFront();
                system("pause");
                break;
            }
        case 4:
            {
                dequeRear();
                system("pause");
                break;
            }
        case 5:
            {
                show();
                system("pause");
                break;
            }
        default:
            {
                cout << "Error: invalid input" << endl;
            }
        }
    }while(pil<=5);
    return 0;
}