Здравейте. Попринцип не обичам да моля за помощ, но съм забил на тази задача и имам нужда от съвет.Задачата е следата :  Да се създаде опашка и да се изключи от нея N-тия елемент от края. Това е кода :

#include<iostream>
using namespace std;
int s=0;
struct elem
{
	int key;
	elem *next;
}*first=NULL,*last=NULL,*p;
void push(int n)
{
	p=last;
	last = new elem;
	last->key=n;
	last->next=NULL;
	if(p!=NULL)
	{
		p->next=last;
	}
	if(first==NULL)
	{
		first=last;
	}
	s++;

}
int pop (int &n)
{
	
	if(first)
	{
		n=first->key;
		p=first;
		first=first->next;
		if(first==NULL)
		{
			last=first;
			
		}delete p;
		return n;

	}
	else 
		return 0;
}
void del(int a)
{
	elem *temp;
	p=first;
	for(int i=0;i<s-a;i++)
	{
		temp=p->next;
        p=temp;
	}
	delete p;
	
}


int main ()
{
	int k;
	do{
		cout<<"Input numbers:";
		cin>>k;
		if(k!=0)
			push(k);
	}while(k!=0);
	
	int a;
	cout<<"Enter number delete:";
	cin>>a;
	del(a);


	cout<<"Queue";
	while(pop(k))
	{
		cout<<"\t"<<k;
	}


}

Благодаря предварително

#include <iostream>
using namespace std;

template <class T> class Node
{
public:
	T data;
	Node* next;
};

template <class T> class Queue
{
	int size;
	Node<T>* head;
	Node<T>* tail;
public:
	Queue();
	~Queue();
	void enqueue(T data);
	T dequeue(bool* isOK);
	void excludeNthFromEnd(int n, bool* isOK);
	void print();
};

template <class T> Queue<T>::Queue()
{
	head = nullptr;
	tail = nullptr;
	size = 0;
}

template <class T> Queue<T>::~Queue()
{
	bool isOK = true;
	while (isOK == true) dequeue(&isOK);
}

template <class T> void Queue<T>::enqueue(T data)
{
	Node<T>* np = new Node<T>;
	np->data = data;
	np->next = nullptr;
	if (size == 0)
	{
		head = np;
		tail = np;
	}
	else
	{
		tail->next = np;
		tail = np;
	}
	size++;
}

template <class T> T Queue<T>::dequeue(bool* isOK)
{
	T value = T();
	Node<T>* c;
	if (size == 0) *isOK = false;
	else
	{
		*isOK = true;
		value = head->data;
		c = head;
		head = head->next;
		delete c;
		size--;
	}
	return value;
}

template <class T> void Queue<T>::excludeNthFromEnd(int n, bool* isOK) // 0 to size - 1
{
	Node<T>* c;
	Node<T>* d;
	if ((n >= size) || (n < 0))
	{
		*isOK = false;
	}
	else
	{
		c = head;
		for (int i = 1; i < n; i++)
		{
			c = c->next;
		}
		if (n == 0) dequeue(isOK);
		else
		{
			d = c->next;
			c->next = c->next->next;
			delete d;
			size--;
			*isOK = true;
		}
	}
}

template <class T> void Queue<T>::print()
{
	Node<T>* c;
	if (size == 0) return;
	c = head;
	for (int i = 0; i < size; i++)
	{
		cout << c->data << " ";
		c = c->next;
	}
}

int main()
{
	bool isOK;
	Queue<int> q;
	for (int i = 0; i < 10; i++)
	{
		q.enqueue(i);
	}
	q.excludeNthFromEnd(5, &isOK);
	q.print();
    return 0;
}