Question

I have the following class:

public class STElement
{
  public int _value;
  public STElement _next;
  public int _index;

  public STElement()
  {
    _value = 0;
    _next = null;
    _index = 0;
  }
}

In the runtime of the programm I want to create some objects like this:

_rootStack1 = new STElement();
_rootStack2 = new STElement();
_rootStack3 = new STElement();

But I only want _rootStack1 to have the _index = 0;

So how can I do it, that only one of the three objects get _index?

Answer 1

You can create a constructor that takes the value of an index and assigns it to the variable.

public STElement(int index)
{
  _value = 0;
  _next = null;
  _index = index;
}

This will not enforce that the object is the only one that has such a 0 index – this is not something an object can do directly.

Note on style – it is not good practice to have public fields. You should use properties to expose them.