#include <iostream.h>
 #include    <conio.h>

 const max_length=10;

 class Queue
    {
       private:
      int queue[max_length];
      int rear;
      int front;

       public:
      Queue( );

      void Delete( );
      void Insert( );
      void print_queue( );
      void show_working( );
    };

 /*************************************************************************///--------------------------  Queue( )  ---------------------------------///*************************************************************************/void Queue::Queue( )
    {
       rear=-1;
       front=-1;

       for(int count=0;count<max_length;count++)
      queue[count]=0;
    }

 /*************************************************************************///------------------------------  Insert( )  ----------------------------///*************************************************************************/void Queue::Insert( )
    {
       int item;

       cout<<"\n\n\n\n\n\t Enter value to insert into the Queue : ";
       cin>>item;

       if((rear==front-1) || (front==0 && rear==max_length-1))
      cout<<"\n\n\t ***  Error : Queue is full. \n"<<endl;

       elseif(rear==-1 && front==-1)
      {
         rear++;
         queue[rear]=item;
         front=rear;

         cout<<"\n\n\t *** "<<item<<" is inserted into the Queue."<<endl;
      }

       elseif(rear==max_length-1 && front!=0)
      {
         rear=0;
         queue[rear]=item;

         cout<<"\n\n\t *** "<<item<<" is inserted into the Queue."<<endl;
      }

       else
      {
         rear++;
         queue[rear]=item;

         cout<<"\n\n\t *** "<<item<<" is inserted into the Queue."<<endl;
      }

       cout<<"\n\n\n\t\t Pres any key to return to Menu. ";

       getch( );
    }

 /*************************************************************************///------------------------------  Delete( )  ----------------------------///*************************************************************************/void Queue::Delete( )
    {
       if(rear==-1 && front==-1)
      cout<<"\n\n\n\t ***  Error : Queue is empty. \n"<<endl;

       else
      {
         cout<<"\n\n\n\t *** "<<queue[front]<<" is deleted from the Queue."<<endl;

         queue[front]=0;

         if(front==rear)
        {
           front=-1;
           rear=-1;
        }

         elseif(front==max_length-1)
        front=0;

         else
        front++;
      }

       cout<<"\n\n\n\t\t Pres any key to return to Menu. ";

       getch( );
    }

 /*************************************************************************///---------------------------  print_queue( )  --------------------------///*************************************************************************/void Queue::print_queue( )
    {
       if(front!=-1 && rear!=-1)
      {
         cout<<"\n\n\n\n\n\t Values inserted into the Queue are : \n"<<endl;

         for(int count=0;count<max_length;count++)
        cout<<"\t Stack ["<<count<<"]  =  "<<queue[count]<<endl;
      }

       else
      cout<<"\n\n\n\n\n\t *** Nothing to show. "<<endl;

       cout<<"\n\n\n\t\t Pres any key to return to Menu. ";

       getch( );
    }


 /*************************************************************************///-------------------------  show_working( )  ---------------------------///*************************************************************************/void Queue::show_working( )
    {
       char Key=NULL;

       do
      {
         clrscr( );

         gotoxy(5,5);
         cout<<"**********   Implementation of Array as Circular Queue   **********"<<endl;

         gotoxy(10,8);
         cout<<"Select one of the listed operation :"<<endl;

         gotoxy(15,10);
         cout<<"- Press \'I\' to Insert a value"<<endl;

         gotoxy(15,12);
         cout<<"- Press \'D\' to Delete a value"<<endl;

         gotoxy(15,14);
         cout<<"- Press \'P\' to Print the values"<<endl;

         gotoxy(15,16);
         cout<<"- Press \'E\' to Exit"<<endl;

         Input:

         gotoxy(10,20);
         cout<<"                      ";

         gotoxy(10,20);
         cout<<"Enter your Choice : ";

         Key=getche( );

         if(int(Key)==27 || Key=='e' || Key=='E')
        break;

         elseif(Key=='i' || Key=='I')
        Insert( );

         elseif(Key=='d' || Key=='D')
        Delete( );

         elseif(Key=='p' || Key=='P')
        print_queue( );

         elsegoto Input;
      }
       while(1);
    }

 int main( )
    {
       Queue obj;

       obj.show_working( );

       return 0;
    }