Program for Deque Using Array

deque.cpp

#include<iostream>
using namespace std;
int front=-1;
int rear=-1;
int q[10];
int data;
bool isfull()
{
    if(rear==9)
    {
        return 1;
    }
    else 
    {
        return 0;
    }
}
bool isempty()
{
    if(front==-1)
    {
        return 1;
    }
    else
    {
        return 0;
    }
}
int insert_front()
{
    if(isfull())
    {
        cout<<"Queue Overflow!"<<endl;
    }
    else
    {
        if(front==-1)
        {
            front=0;
            rear=0;
        }
        else if(front<1)
        {
            cout<<"Cannot add Item"<<endl;
        }
        else
        {
            front=front-1;
        }
        cout<<"Enter Data:";
        cin>>data;
        q[front]=data;
    }
}
int insert_rear()
{
    if(isfull())
    {
        cout<<"Queue Overflow!"<<endl;
    }
    else
    {
        if(front==-1)
        {
            front=0;
            rear=0;
        }
        else
        {
            rear=rear+1;
        }
        cout<<"Enter Data:";
        cin>>data;
        q[rear]=data;
    }
}
int delete_front()
{
    if(isempty())
    {
        cout<<"Queue Underflow!"<<endl;
    }
    else
    {
        if(front==rear)
        {
            cout<<"Deleted element is "<<q[front];
            front=-1;
            rear=-1;
        }
        else
        {
            cout<<"Deleted element is "<<q[front];
            front=front+1;
        }
    }
}
int delete_rear()
{
    if(isempty())
    {
        cout<<"Queue Underflow!"<<endl;
    }
    else
    {
        if(front==rear)
        {
            cout<<"Deleted element is "<<q[front];
            front=-1;
            rear=-1;
        }
        else
        {
            cout<<"Deleted element is "<<q[rear];
            rear=rear-1;
        }
    }
}
int display()
{
    if(isempty())
    {
        cout<<"Queue Underflow!"<<endl;
    }
    else
    {
        cout<<"Queue elements are:"<<endl;
        for(int i=front;i<=rear;i++)
        {
            cout<<q[i]<<"->";
        }
    }
}
int main()
{
    int ch,ch1,ch2;
    while(ch!=-1)
    {
        cout<<"n----Menu----"<<endl;
        cout<<"1.input Restricted Queue"<<endl;
        cout<<"2.Output Restricted Queue"<<endl;
        cout<<"3.Exit"<<endl;
        cout<<"Enter a choice:";
        cin>>ch;
        switch(ch)
        {
            case 1:
                while(ch1!=-1)
                {
                        cout<<"n--input Restricted Queue--"<<endl;
                        cout<<"1.Add at Rear."<<endl;
                        cout<<"2.Delete from Front."<<endl;
                        cout<<"3.Delete from Rear."<<endl;
                        cout<<"4.Display"<<endl;
                        cout<<"5.Exit"<<endl;
                        cout<<"Enter a choice:";
                        cin>>ch1;
                        switch(ch1)
                        {
                            case 1:
                                insert_rear();
                                break;                      
                            case 2:
                                delete_front();
                                break;
                            case 3:
                                delete_rear();
                                break;
                            case 4:
                                display();
                                break;
                            case 5:
                                exit(0);
                        }
                }
            case 2:
                    while(ch2!=-1)
                {
                        cout<<"n--input Restricted Queue--"<<endl;
                        cout<<"1.Add at Rear."<<endl;
                        cout<<"2.Add at Front."<<endl;
                        cout<<"3.Delete from Front."<<endl;
                        cout<<"4.Display"<<endl;
                        cout<<"5.Exit"<<endl;
                        cout<<"Enter a choice:";
                        cin>>ch2;
                        switch(ch2)
                        {
                            case 1:
                                insert_rear();
                                break;                      
                            case 2:
                                insert_front();
                                break;
                            case 3:
                                delete_front();
                                break;
                            case 4:
                                display();
                                break;
                            case 5:
                                exit(0);
                        }
                }
                case 3:
                    exit(0);
        }
    }
}