deque.cpp

#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(true)
	{
		cout<<"\nWelcome.\nPlease enter your choice:\n1.Insert at Front\t2.Insert at Rear\n3.Delete from Front\t4.Delete from Rear\n5.Display\t\t6.Exit ";
		cin>>ch;
		switch(ch)
		{
			case 1:
			{
				cout<<"\nEnter data to insert at Front: ";
				cin>>data;
				addf(&q,data);
				break;
			}
			case 2:
			{
				cout<<"\nEnter data to insert at Rear: ";
				cin>>data;
				addr(&q,data);
				break;
			}
			case 3:
			{	
				if(isempty(q))
				{
					cout<<"\nDequeue is empty"<<endl;
				}
				else
				{
					data=delf(&q);
					cout<<"\nDeleted data is: "<<data;
				}
				break;
			}
			case 4:
			{
				if(isempty(q))
				{
					cout<<"\nDequeue is empty"<<endl;
				}
				else
				{
					data=delr(&q);
					cout<<"\nDeleted data is: "<<data;
				}
				break;
			}
			case 5:
			{
				if(isempty(q))
				{
					cout<<"\nDequeue is empty"<<endl;
				}
				else
				{
					cout<<"\nDequeue elements are: "<<endl;
					print(q);
				}
				break;
			}
			case 6:
			{
				exit(0);
			}
			default:
			{
				cout<<"Invalid choice";
			}
		}
	}
	return 0;
}