DQueue_Add_Delete.cpp

#include<iostream>

using namespace std;
#define SIZE 5

class dequeue {

    int a[10], front, rear, count;

public:
    dequeue();

    void add_at_beg(int);

    void add_at_end(int);

    void delete_fr_front();

    void delete_fr_rear();

    void display();
};


dequeue::dequeue() {
    front = -1;
    rear = -1;
    count = 0;
}


void dequeue::add_at_beg(int item) {
    int i;
    if (front == -1) {
        front++;
        rear++;
        a[rear] = item;
        count++;
    } else if (rear >= SIZE - 1) {
        cout << "\nInsertion is not possible, overflow.";
    } else {
        for (i = count; i >= 0; i--) {
            a[i] = a[i - 1];
        }
        a[i] = item;
        count++;
        rear++;
    }
}


void dequeue::add_at_end(int item) {

    if (front == -1) {
        front++;
        rear++;
        a[rear] = item;
        count++;
    } else if (rear >= SIZE - 1) {
        cout << "\nInsertion is not possible, overflow.";
        return;
    } else {
        a[++rear] = item;
    }


}


void dequeue::display() {

    for (int i = front; i <= rear; i++) {
        cout << a[i] << " ";
    }
}


void dequeue::delete_fr_front() {
    if (front == -1) {
        cout << "Deletion is not possible, underflow.";
        return;
    } else {
        if (front == rear) {
            front = rear = -1;
            return;
        }
        cout << "The deleted element is " << a[front];
        front = front + 1;
    }


}

void dequeue::delete_fr_rear() {
    if (front == -1) {
        cout << "Deletion is not possible, underflow.";
        return;
    } else {
        if (front == rear) {
            front = rear = -1;
        }
        cout << "The deleted element is " << a[rear];
        rear = rear - 1;
    }


}


int main() {
    int c, item;
    dequeue d1;

    do {
        cout << "\n\n================================DEQUEUE OPERATIONS================================\n";
        cout << "\n1. Insert at beginning";
        cout << "\n2. Insert at end";
        cout << "\n3. Display";
        cout << "\n4. Deletion from front";
        cout << "\n5. Deletion from rear";
        cout << "\n6. Exit";
        cout << "\nEnter your choice: ";
        cin >> c;

        switch (c) {
            case 1:
                cout << "Enter the element to be inserted: ";
                cin >> item;
                d1.add_at_beg(item);
                break;

            case 2:
                cout << "Enter the element to be inserted: ";
                cin >> item;
                d1.add_at_end(item);
                break;

            case 3:
                d1.display();
                break;

            case 4:
                d1.delete_fr_front();
                break;
            case 5:
                d1.delete_fr_rear();
                break;

            case 6:
                exit(1);

            default:
                cout << "Wrong choice.";
                break;
        }

    } while (c != 7);
    return 0;

}