Last year I built a generic list, everything was good. This year I'm adding classes to the list. These classes have lists. Everything is okay until the program ends, then it crashes. If I comment out my list destructor the crash doesn't happen.
So I'm assuming the destructors aren't unraveling in the order I expect. I could just leave out the destructor but... 1) I was taught that if I have a "new" I better have a corresponding "delete" and 2) I'd like to know what I'm doing wrong.
Truncated code vomit follows...
Test program and class...
#include "list.h"
class CCrashTest
{
public:
CCrashTest();
~CCrashTest();
void add(int Value, char A, char B);
list <char> willCrash;
private:
int a;
};
CCrashTest::CCrashTest() { };
CCrashTest::~CCrashTest() { };
void CCrashTest::add(int Value, char A, char B)
{
this->a = Value;
this->willCrash.add(A);
this->willCrash.add(B);
}
int main ()
{
list <CCrashTest> crashTest;
CCrashTest CT;
int arrayTest4[5] = {18, 5, 231, 68, 185};
for (i=0; i<5; i++)
{
cout << "Adding " << arrayTest4[i] << " to class" << endl;
CT.add(arrayTest4[i], 'a', 'b');
crashTest.add(CT);
}
cout << "Deleting class" << endl;
return 0;
}And the list class (abbreviated)...
#ifndef LIST_H
#define LIST_H
template <class LISTDATA>
class list
{
protected:
template <class LISTDATA>
struct listNode
{
LISTDATA key;
listNode <LISTDATA> *prev;
listNode <LISTDATA> *next;
};
public:
list();
~list();
virtual void add(const LISTDATA Value);
virtual LISTDATA get();
virtual void remove();
void clearList();
protected:
listNode <LISTDATA> *start;
listNode <LISTDATA> *end;
int numberOfNodes;
protected:
void addToStart(const LISTDATA Value);
void addToEnd(const LISTDATA Value);
LISTDATA removeFromStart();
LISTDATA removeFromEnd();
void destroyList();
};
#endif
// ---------------- CONSTRUCTOR & DESTRUCTOR ----------------------
template <class LISTDATA>
list<LISTDATA>::list()
{
this->start = NULL;
this->end = NULL;
this->numberOfNodes = 0;
}
template <class LISTDATA>
list<LISTDATA>::~list()
{
this->destroyList();
}
template <class LISTDATA>
void list<LISTDATA>::destroyList()
{
while (this->end != NULL)
this->removeFromStart();
}
// ------------------------- ADD -------------------------------
template <class LISTDATA>
void list<LISTDATA>::add(const LISTDATA Value)
{
this->addToStart(Value);
}
template <class LISTDATA>
void list<LISTDATA>::addToStart(LISTDATA Value)
{
listNode <LISTDATA> *nodeToAdd;
nodeToAdd = new listNode<LISTDATA>;
nodeToAdd->key = Value;
if (this->start == NULL)
{
nodeToAdd->prev = NULL;
nodeToAdd->next = NULL;
this->start = nodeToAdd;
this->end = nodeToAdd;
}
else
{
this->start->prev = nodeToAdd;
nodeToAdd->prev = NULL;
nodeToAdd->next = this->start;
this->start = nodeToAdd;
}
this->numberOfNodes++;
}
// ------------------------- REMOVE ----------------------------
template <class LISTDATA>
LISTDATA list<LISTDATA>::removeFromStart()
{
listNode <LISTDATA> *tempNode;
LISTDATA Value;
if (this->start == NULL)
{
throw exceptions("Error (list.removeFromStart): List is empty");
}
else
{
tempNode = this->start;
Value = tempNode->key;
this->start = tempNode->next;
if (this->start == NULL)
this->end = NULL;
this->numberOfNodes--;
delete tempNode;
}
return Value;
}Thank you much.
