двусписк

#include "exception.cpp"
#include <iostream>
#include <fstream>

using namespace std;

template <class X>
class DoubleLinkedList
{
    struct Element
    {
        X inf;
        Element *next;
        Element *prev;
        Element (X x): inf(x), next(0), prev(0)
        {
        }
    };
    Element *head;
    Element *tail;
    int size;
    Element *Find( int index)
    {
        if(index < 1||index > size)
            return NULL;
        else
        {
            Element *cur = head;
            for(int i = 1; i < index; i++)
                cur = cur->next;
            return cur;
        }
    }
public:
    DoubleLinkedList():head(0), tail(0), size(0)
    {
    }
    ~DoubleLinkedList()
    {
        while(!Empty())
            Remove(1);
    }
    bool Empty()
    {
        return head == 0;
    }
    int GetLength()
    {
        return size;
    }
    X Get(int index)
    {
        if (index < 1 || index > size)
        {
            throw DoubleListException("ListException: get - double-linked list error");
        }
        else
        {
            Element *r = Find(index);
            X i = r->inf;
            return i;
        }
    }
    void InsertLeft(int index, X data )
    {
        if (index < 1 || index > size+1)
        {
            throw DoubleListException("ListException: insert - double-linked list error");
        }
        else
        {
            Element *newPtr = new Element(data);
            size = GetLength() + 1;
            Element *cur = Find(index)
            if (cur == NULL)
            {
                head = newPtr;
                tail = newPtr;
            }
            else
            {
                newPtr->next = cur;
                newPtr->prev = cur->prev;
                cur->prev = newPtr;
                if(cur == head)
                    head = newPtr;
                else newPtr->prev->next = newPtr;
            }
        }
    }
    void InsertRight(int index, X data )
    {
        if ((index < 1 && head != NULL) || (index > size+1))
        {
            throw DoubleListException("ListException: insert - double-linked list error");
        }
        else
        {
            Element *newPtr = new Element(data);
            size = GetLength() + 1;
            Element *cur = Find(index);
            if (cur == NULL)
            {
                head = newPtr;
                tail = newPtr;
            }
            else
            {
                newPtr->next = cur->next;
                newPtr->prev = cur;
                cur->prev = newPtr;
                if(cur == tail)
                    tail = newPtr;
                else newPtr->next->prev = newPtr;
            }
        }
    }
    void Remove (int index)
    {
        if (index < 1 || index > size)
        {
            throw DoubleListException("ListException: remove - double-linked list error");
        }
        else
        {
            Element *cur = Find(index);
            --size;
            if (size == 0)
            {
                head = NULL;
                tail = NULL;
            }
            else if (cur == head)
            {
                head = head->next;
                head->prev = NULL;
            }
            else if (cur == tail)
            {
                tail = tail->prev;
                tail->next = NULL;
            }
            else
            {
                cur->prev->next = cur->next;
                cur->next->prev = cur->prev;
            }
            cur->next = NULL;
            cur->prev = NULL;
            delete cur;
        }
    }

    void PrintLeftToRight(ofstream &out)
    {
        for(Element * cur = head; cur != NULL; cur = cur->next)
            out << cur->inf << " ";
        out << endl;
    }

};

int main()
{
    DoubleLinkedList <int>  t;
    int i;
    ifstream in ("input.txt");
    ofstream out ("output.txt");
    while (in >> i)
        t.InsertRight(t.GetLength(), i);
    in.close();
    for( int j = 1; j <= t.GetLength(); )
    {
        if(t.Get(j) % 2 == 0)
            t.InsertRight(j, t.Get(j)*2);
    }
    t.PrintLeftToRight(out);
    t.~DoubleLinkedList();
    out.close();
    return 0;
}
//срр
#include <exception>
#include <string>

using namespace std;

class DoubleListException: public exception
{
public:
    DoubleListException(const string & message=""): exception(message.c_str())
    {
    }
};