Implemented class list , problems have problems with the Insert method. This method also works as in the LIST library, i.e. I transmit a position to the function to insert and the value itself, while the list size does not increase, it simply replaces the value of the item in a given position. At the very beginning and in the end everything is correctly inserted, and with the rest of the problem.

void insert (const int index, const t & amp; value) {
  Element & lt; T & GT; * NewElem = New Element & lt; T & GT; (Value);
  int Curindex = 0;
  Element & lt; T & GT; * CUR = _FRONT;
  While (Cur! = NullPTR)
  {
    if (index == 0)
    {
      // If index = 0 is entered, I change the values ​​using the designer
      // First Element
      _Front = New Element & lt; T & GT; (value, _front- & gt; getNext (), _ Front- & gt; getprev ());
    }
    if (index == _SIZE-1)
    {
     // If index = Size is entered (the size of my list), with
     // Designer I change the values ​​of the last element
    _back = new element & lt; t & gt; (value, _back- & gt; getNext (), _back- & gt; getprev ());
    }
    if (index & lt; 0)
    {
      Return;
    }
    if (Curindex == index-1)
    {
     // setNext () - the method that indicates the next element
     // SETZKUM () - The method that indicates the previous element
      NEWELEM- & GT; SETNEXT (CUR- & GT; getNext ());
      NEWELEM- & GT; setPrev (CUR- & GT; GetPrev ());
      CUR- & GT; SETNEXT (NEWELEM);
    }
    Curindex ++;
    CUR = CUR- & GT; getNext ();
  }
}

How do this method more correctly implement?

Answer 1, Authority 100%

You have a strange insert. It turns out: here in the first line:

element & lt; t & gt; * newelem = new element & lt; t & gt; (value);

You have created a new item, and then:

if (index == 0)
  {
    // If index = 0 is entered, I change the values ​​using the designer
    // First Element
    _Front = New Element & lt; T & GT; (value, _front- & gt; getNext (), _ Front- & gt; getprev ());
  }

still stands out. In this case, without deleting the memory under _Front . That is, you lose the memory twice. The same after the line if (index == _Size-1)

You can approximately this:

void insert (const int index, const t & amp; value) {
 Element & lt; t & gt; * current = _front;
 for (int i = 0; i & lt; = index; ++ i)
    Current = Current- & gt; getNext ();
 CURRENT- & GT; SETVALUE (VALUE);
}

Add the setValue method to the Element class and you do not need to allocate dynamic memory again. This is a schematic example without taking into account that the user can pass an invalid index.