/* Stack/Queue operations 
	
   void push(struct stack_queue **p, int number, int type);

	   Example:
	   struct stack_queue link_base;
	   push(&link_base,number_to_be_pushed,0);

	   0 -> Stack
	   1 -> Queue

   int pop(struct stack_queue **p);

	   Example:
	   struct stack_queue link_base;
	   variable=pop(&link_base);
   
   void display(struct stack_queue *p);

	   Example:
	   struct stack_queue link_base;
	   display(link_base);

   int count(struct stack_queue *p);

	   Example:
	   struct srack_queue link_base;
	   variable=count(link_base);

*/

//Structure for the stack_queue
struct stack_queue
{
	int key;
	struct stack_queue *next;
};

//Push an item into the stack/queue
void push(struct stack_queue **b, int n, int t)
{
struct stack_queue *q,*r;
q=*b;
if(t==0)
{
	if(q==NULL)
	{
		q=(struct stack_queue *)malloc(sizeof(struct stack_queue *));
		q->key=n;
		q->next=NULL;
		*b=q;
	}
	else
	{
		r=(struct stack_queue *)malloc(sizeof(struct stack_queue *));
		r->key=n;
		r->next=q;
		*b=r;
	}
}
else if (t==1)
{
	if(q==NULL)
	{
		q=(struct stack_queue *)malloc(sizeof(struct stack_queue *));
		q->key=n;
		q->next=NULL;
		*b=q;
	}
	else
	{
		while(q->next!=NULL)
			q=q->next;

		r=(struct stack_queue *)malloc(sizeof(struct stack_queue *));
		r->key=n;
		r->next=NULL;
		
		q->next=r;
	}
}
}

//Pop an item from the stack/queue
int pop(struct stack_queue **b)
{
	struct stack_queue *p;
	int n;

	p=*b;
	if(p==NULL){return 0;}

	n=p->key;
	*b=p->next;
	free(p);
	return n;
}

//Count the number of items in the stack
int count(struct stack_queue *b)
{
	struct stack_queue *p;
	int c=0;
	p=b;
	while(p!=NULL)
	{
		c++;
		p=p->next;
	}
	return c;
}

//Display the contents of the stack/queue
void display(struct stack_queue *b)
{
	struct stack_queue *p;
	p=b;
	if(count(p)==0){printf("\n Data structure is empty!");return;}
	while(p!=NULL)
	{
		printf("\n Element is %d",p->key);
		p=p->next;
	}
}

//Use struct stack_queue from now on as DStructure
typedef struct stack_queue DStructure;