Double Ended Queue using C++

Author: Sanif S S 

Site: theeduzone.blogspot.com 

Email: sanifss@gmail.com

#include<stdio.h>

#include<conio.h>

#define max 3
class queue
 {
   int  item[max];
   int front;
   int rear;
  public:
     void insert_rear();
     void delete_front();
     void insert_front();
     void delete_rear();
     void display();
     queue()
     {
     rear=-1;
      front=-1;
      }

   };
void queue::insert_rear()
  {
    int value;
     if(rear==max-1)
       {
       cout<<"Queue is full insertion not possible\n";
}
      else
{
cout<<"\nEnter the value to be inserted\n";
cin>>value;
rear=rear+1;
item[rear]=value;
if(front==-1)
{ front=0;}
}
   }
void queue::delete_front()
   {
    int value;
    if(front==-1)
     {
       cout<<"Queue empty\n ";
       }
    else
    {
      value=item[front];
      cout<<"deleted item is"<
       if(front==rear)

 front=rear=-1;
else

  front=front+1;

      }
    }
void queue::insert_front()
   {
   int value;
   if(front==0)
    {
    cout<<"Queue is full\n";

    }
   else
   {
   if(front==-1)
   {
     front=0 ;  }
    front=front-1;

  cout<<"Enter the element to insert\n";
  cin>>value;
   item[front]=value;

   }
   }
   void queue::delete_rear()
     {
     int value;
       if(front<0)
cout<<"Queue is empty\n";
else
{
  value=item[rear];
  if(front==rear)
     {
      front=rear=-1;
}
      else
rear=rear-1;
}
    cout<<"deleted element is "<
 }
 void queue::display()
   {
   if(front==-1&&rear==-1)
     {
      cout<<"queue is empty\n" ;
      }
   else
    {
     cout<<"Elements in queue are\n";
      for(int i=front;i<=rear;i++)
{
cout<
}
       getch();
    }
 }
void main()
{
 int choice,c;
 char ch;
 queue q;
 clrscr();
 do
   {
     cout<<"       MENU\n";
     cout<<"1.Input restricted queue\n\n" ;
     cout<<"2.Output restricted queue\n\n";
     cout<<"3.Display\n";
     cout<<"nter your choice\n";
     cin>>choice;
     switch(choice)
      {
      case 1 :cout<<"     menu\n";
     cout<<"1.Insertion at rear\n";
     cout<<"2.Deletion from front\n";
     cout<<"3.Deletion from rear\n";
     cout<<"Enter your choice\n";
     cin>>c;
     switch(c)
     {
     case 1:q.insert_rear();break;
     case 2:q.delete_front();break;
     case 3:q.delete_rear();break;
     default :cout<<"Invalid choice\n";break;
     }
     break;
      case 2 :cout<<"  menu \n";
     cout<<"1.Insertion at rear\n";
     cout<<"2.Insertion at front\n";
     cout<<"3.Deletion from front\n";
     cout<<"Enter your choice\n";
     cin>>c;
     switch(c)
     {
     case 1:q.insert_rear();break;
     case 2:q.insert_front();break;
     case 3:q.delete_front();break;
     default:cout<<"Invalid choice\n";break;
     }
     break;
      case 3:q.display();break;
      default:cout<<"Invalid choice\n"; break;

      }
     cout<<"\nDo you want to continue(yes=y,no=n)";
     cin>> ch;
    }while(ch=='Y'||ch=='y');
     getch();

   }