Practical_31(C++).cpp

/*
A double-ended queue (deque) is a linear list in which additions and deletions may be made at either end. Obtain a data
representation mapping a deque into a one-dimensional array. Write C++ program to simulate deque with functions to add 
and delete elements from either end of the deque. 
*/

#include<iostream>
#include<stdio.h>
#define MAX 10
using namespace std;

struct que {
    int arr[MAX];
    int front, rear;
};

void init(struct que *q) {
    q->front = -1;
    q->rear = -1;
}

void print(struct que q) {
    int i;
    i = q.front;
    while (i != q.rear) {
        cout << "\t" << q.arr[i];
        i = (i + 1) % MAX;
    }
    cout << "\t" << q.arr[q.rear];
}

int isempty(struct que q) {
    return q.rear == -1 ? 1 : 0;
}

int isfull(struct que q) {
    return (q.rear + 1) % MAX == q.front ? 1 : 0;
}

void addf(struct que *q, int data) {
    if (isempty(*q)) {
        q->front = q->rear = 0;
        q->arr[q->front] = data;
    } else {
        q->front = (q->front - 1 + MAX) % MAX;
        q->arr[q->front] = data;
    }
}

void addr(struct que *q, int data) {
    if (isempty(*q)) {
        q->front = q->rear = 0;
        q->arr[q->rear] = data;
    } else {
        q->rear = (q->rear + 1) % MAX;
        q->arr[q->rear] = data;
    }
}

int delf(struct que *q) {
    int data1;
    data1 = q->arr[q->front];
    if (q->front == q->rear)
        init(q);
    else
        q->front = (q->front + 1) % MAX;
    return data1;
}

int delr(struct que *q) {
    int data1;
    data1 = q->arr[q->rear];
    if (q->front == q->rear)
        init(q);
    else
        q->rear = (q->rear - 1 + MAX) % MAX;
    return data1;
}

int main() {
    struct que q;
    int data, ch;
    init(&q);
    while (ch != 6) {
        cout << "\t\n1. Insert front"
                "\t\n2. Insert rear"
                "\t\n3. Delete front"
                "\t\n4. Delete rear"
                "\t\n5. Print"
                "\t\n6. Exit";
        cout << "\nEnter your choice : ";
        cin >> ch;
        switch (ch) {
            case 1:
                cout << "\nEnter data to insert front : ";
                cin >> data;
                addf(&q, data);
                break;

            case 2:
                cout << "\nEnter the data to insert rear : ";
                cin >> data;
                addr(&q, data);
                break;

            case 3:
                if (isempty(q))
                    cout << "\nDequeue is empty!!!";
                else {
                    data = delf(&q);
                    cout << "\nDeleted data is : " << data;
                }
                break;

            case 4:
                if (isempty(q))
                    cout << "\nDequeue is empty!!!";
                else {
                    data = delr(&q);
                    cout << "\nDeleted data is : " << data;
                }
                break;

            case 5:
                if (isempty(q))
                    cout << "\nDequeue is empty!!!";
                else {
                    cout << "\nDequeue elements are : ";
                    print(q);
                }
                break;
        }
    }
    return 0;
}