//for queues
 #include<iostream.h>
 #include<conio.h>
 #define max 10

 class queue
 {
	public:
		void insert(int n);
		void display();
		long int del();
		int front,rear,a[max];
 };

 void main()
 {
	clrscr();
	int n,ch;
	queue q;
	q.front=q.rear=-1;
	do
	{
		cout<<"\nMain Menu";
		cout<<"\n1:Insert\n";
		cout<<"2:Delete\n";
		cout<<"3:Display\n";
		cout<<"4:Exit\n";
		cout<<"Enter your choice:";
		cin>>ch;
		switch(ch)
		{
			case 1:cout<<"Enter the element to be inserted:";
			       cin>>n;
			       q.insert(n);
			       q.display();
			       break;
			case 2:long int c=q.del();
			       cout<<"The element deleted is:"<<c<<endl;
			       q.display();
			       break;
			case 3:q.display();
			       break;
			case 4:cout<<"Exiting.....\n";
			       break;
			default:cout<<"Wrong choice\n";
			       break;
		}
	}while(ch!=4);
 }

 void queue::insert(int n)
 {
	if(rear==max-1)
	{
		cout<<"Overflow\n";
		return;
	}
	rear++;
	a[rear]=n;
	if(front==-1)
	front=0;
 }

 long int queue::del()
 {
	if(front==-1)
	{
		cout<<"Underflow\n";
		return -999;
	}
	int x=a[front];
	if(front==rear)
	front=rear=-1;
	else
	front++;
	return(x);
  }

  void queue::display()
  {
	if(front==-1)
	cout<<"Queue is empty now.\n";
	for(int i=front;i<=rear;i++)
	{
		if(i>=0)
		cout<<a[i]<<" ";
	}
	cout<<endl;
  }