Data Structures using C++

  #include< iostream.h > 
  #include< conio.h > 
  const int MAX = 5; 
  class cqueue 
  { 
      int a[MAX],front,rear; 
     public : 
        cqueue() 
        { 
          front=rear=-1; 
       } 
       void insert(int ); 
       int deletion(); 
       void display(); 
  }; 
  void cqueue :: insert(int val) 
  { 
      if((front==0 && rear==MAX-1) || (rear+1==front)) 
        cout<<" Circular Queue is Full"; 
     else 
     { 
       if(rear==MAX-1) 
          rear=0; 
       else 
          rear++; 
       a[rear]=val; 
     } 
     if(front==-1) 
       front=0; 
  } 
  int cqueue :: deletion() 
  { 
     int k; 
     if(front==-1) 
       cout<<"Circular Queue is Empty"; 
     else 
     { 
       k=a[front]; 
       if(front==rear) 
          front=rear=-1; 
       else 
       { 
          if(front==MAX-1) 
            front=0; 
          else 
            front++; 
       } 
     } 
     return k; 
  } 
  void cqueue :: display() 
  { 
     int i; 
     if(front==-1) 
        cout<<"Circular Queue is Empty"; 
     else 
     { 
        if(rear < front) 
        { 
          for(i=front;i<=MAX-1;i++) 
            cout<< a[i] <<" "; 
          for(i=0;i<=rear;i++) 
            cout<< a[i] <<" "; 
        } 
        else 
        { 
          for(i=front;i<=rear;i++) 
            cout<< a[i]<<" "; 
          cout<< endl; 
        } 
     } 
  } 
  void main() 
  { 
     cqueue c1; 
     int ch,val; 
     char op; 
     do 
     { 
       clrscr(); 
       cout<<"-----------Menu-------------"; 
       cout<<"1.Insertion 
       2.Deletion 
       3.Display 
       4.Exit"; 
       cout<<"Enter Your Choice <1..4> ?"; 
       cin>>ch; 
       switch(ch) 
       { 
          case 1 : cout<<"Enter Element to Insert ?"; 
            cin>>val; 
            c1.insert(val); 
            break; 
          case 2 : val=c1.deletion(); 
            cout<<"Deleted Element :"<< val<< endl; 
            break; 
          case 3 : c1.display(); 
            break; 
       } 
       cout<<"Do you want to continue < Y/N > ?"; 
       cin>>op; 
     }while(op=='Y' || op=='y'); 
       getch(); 
  }