Liste2.h

#include <cmath>
#include "ListenElement2.h"

class Liste
{
    public:
        Liste()
        {
            head = NULL;
            tail = NULL;
            size = 0;
        }

        void add(int value,unsigned int position = 0)
        {
            if(position < 0 || position > size)
            {
                return; //Abbrechen, falls position ungültig ist
            }

            ListenElement *newElem = new ListenElement(value);

            if(position == 0)
            {
                if(size == 0)
                {
                    tail = newElem;
                }
                newElem->setNext(head);
                head = newElem;
            }
            else if(position == size)
            {
                tail->setNext(newElem);
                newElem->setPrev(tail);
                tail = newElem;
            }
            else
            {
                ListenElement *current = NULL;
                if(position <= floor(size/2))
                {
                    current = head;
                    for(unsigned int i=0;i<position;i++) current = current->getNext();
                }
                else
                {
                    current = tail;
                    for(unsigned int i=size-1;i>position;i--) current = current->getPrev();
                }
                newElem->setNext(current);
                newElem->setPrev(current->getPrev());
                newElem->getPrev()->setNext(newElem);
                current->setPrev(newElem);
            }
            size++;
        }
        
        void remove(unsigned int index)
        {
            if(size == 0 || index < 0 || index > (size-1)) return;

            if(index == 0)
            {
                head = head->getNext();
                size--;
            }
            else
            {
                ListenElement *current = NULL;
                if(index <= floor(size/2))
                {
                    current = head;
                    for(unsigned int i=0;i<index;i++) current = current->getNext();
                }
                else
                {
                    current = tail;
                    for(unsigned int i=size-1;i>index;i--) current = current->getPrev();
                }
                current->getPrev()->setNext(current->getNext());
                if(current->getNext() != NULL)
                {
                    current->getNext()->setPrev(current->getPrev());
                }
                else
                {
                    tail = current->getPrev();
                }
                delete current;
                size--;
            }
        }
        
        int getValue(unsigned int index)
        {
            ListenElement *current = NULL;
            if(index <= floor(size/2))
            {
                current = head;
                for(unsigned int i=0;i<index;i++)
                {
                    current = current->getNext();
                }
            }
            else
            {
                current = tail;
                for(unsigned int i=size-1;i>index;i--)
                {
                    current = current->getPrev();
                }
            }
            return current->getValue();
        }
        
        int getSize()
        {
            return size;
        }
        
    private:
        ListenElement *head;
        ListenElement *tail;
        unsigned int size;
};

ListenElement2.h

class ListenElement
{
    public:
        ListenElement(int pValue,ListenElement *pPrev = NULL,ListenElement *pNext = NULL)
        {
            value = pValue;
            next  = pNext; 
            prev  = pPrev;
        }

        ListenElement *getNext()
        {
            return next;
        }

        ListenElement *getPrev()
        {
            return prev;
        }

        void setNext(ListenElement *pNext)
        {
            next = pNext;
        }
        
        void setPrev(ListenElement *pPrev)
        {
            prev = pPrev;
        }
        
        int getValue()
        {
            return value;
        }

        void setValue(int pValue)
        {
            value = pValue;
        }
    private:
        int value;
        ListenElement *next;
        ListenElement *prev;
};