CStack Class

[Anmol444]

In this code:

// A push-down stack to store Box objects
#pragma once
class CBox;                           // Forward class declaration
class CStack
{
private:
  // Defines items to store in the stack
  struct CItem
  {
    CBox* pBox;                       // Pointer to the object in this node
    CItem* pNext;                     // Pointer to next item in the stack or null
        
    // Constructor
    CItem(CBox* pB, CItem* pN): pBox(pB), pNext(pN){}
  };
        
  CItem* pTop;                        // Pointer to item that is at the top
        
public:
  // Constructor
  CStack():pTop(nullptr){}
        
  // Push a Box object onto the stack
  void Push(CBox* pBox)
  {
    pTop = new CItem(pBox, pTop);     // Create new item and make it the top
  }
        
  // Pop an object off the stack
  CBox* Pop()
  {
    if(!pTop)                         // If the stack is empty
      return nullptr;                 // return null
        
    CBox* pBox = pTop->pBox;          // Get box from item
    CItem* pTemp = pTop;              // Save address of the top item
    pTop = pTop->pNext;               // Make next item the top
    delete pTemp;                     // Delete old top item from the heap
    return pBox;
  }
        
  // Destructor
  virtual ~CStack()
  {
    CItem* pTemp(nullptr);
    while(pTop)                       // While pTop not null
    {
      pTemp = pTop;
      pTop = pTop->pNext;
      delete pTemp;
    }
  }
};

Why is the destructor virtual? Isnt that useless in this situation? I know why they are used but in this situation isnt it useless?

[Anmol444]

Or is it just to represent good program design, because if any class is derived from CStack and made dynamic and pointed to by a base pointer it needs to also call its destructor.

[zb0S216C]

Perhaps "CStack" is intended to be a base-class of some sort? Who knows? The author does.

_Wazzak

[Anmol444]

Alright thanks!