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Overloaded operators and copy constructor

kikiyox77 (50)
so I have some trouble with my code, not sure if its something wrong with the copy constructor or the overloaded insertion

this is the DoublyList.h
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#ifndef DOUBLYLIST_H
#define DOUBLYLIST_H

#include <string>
#include <iostream>
using namespace std;

class Node
{
public:
	Node() : data(0), prev(NULL), next(NULL) {}
	Node(int newData, Node *newPrev, Node *newNext)
		: data(newData), prev(newPrev), next(newNext) {}
	int getData() const { return data; }
	Node *getPrev() const { return prev; }
	Node *getNext() const { return next; }
	void setData(const int& newData) { data = newData; }
	void setPrev(Node *newPrev) { prev = newPrev; }
	void setNext(Node *newNext) { next = newNext; }
	bool operator==(const Node& otherNode) { return (this == &otherNode); }
	~Node() {}
private:
	int data;
	Node *prev;
	Node *next;
};


class DoublyList
{
	// Functions of Functions.cpp
	friend ostream& operator<<(ostream &out, const DoublyList& lst);


public:
	DoublyList(); 

	void insertBack(int numOfElem);
	void insertBack(const int a[], int numOfElem);

	int getFirst() const;
	int getLast() const;
	int getNumOfElem() const;
	Node* getPrevOfFirst() const;
	Node* getNextOfLast() const;	
	Node& getFirstNodeAddress() const;
	Node& getLastNodeAddress() const;
	
	void reversePrint() const;

	void destroyList();
	~DoublyList();

	// Functions of Function.cpp

	DoublyList(const DoublyList& lst);
	DoublyList& operator=(DoublyList other);



private:
    Node *first;	// pointer to the first node on the list
    Node *last;		// pointer to the last node on the list
	int count;		// number of nodes in the list
};

#endif



This is the DoublyList.cpp insertBack() function:
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void DoublyList::insertBack(int elem)
{
	Node *newNode = new Node(elem, last, NULL);

	if (first == NULL)
		first = newNode;
	else
		last->setNext(newNode);

	last = newNode;
	++count;
}



Then this is the Functions.cpp file where I'm having most of my troubles:
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#include "DoublyList.h"

// overloaded insertion operator
ostream& operator<<(ostream &out, const DoublyList& lst)
{
	if (lst.first == nullptr)
	{
		out << "List is empty" << endl;
	}
	else
	{
		Node* current = lst.first;
		while (current != nullptr)
		{
			out << current->getData() << " ";
			current = current->getNext();
		}
	}

	return out;
}

// copy constructor
DoublyList::DoublyList(const DoublyList& other)
{
	Node* current = other.first;

	while (current != nullptr)
	{
		insertBack(current->getData());
		current = current->getNext();
	}
}


// overloaded assignment operator
DoublyList& DoublyList::operator=(DoublyList lst)
{
	if (first->getData() == lst.first->getData()
		&& last->getData() == lst.last->getData())
	{
		Node* current = first;
		Node* other = lst.first;
		bool same = false;
		while (current != nullptr && !same)
		{
			if (current->getData() == other->getData())
			{
				current = current->getNext();
				other = other->getNext();
			}
			else
			{
				same = true;
			}
		}
		if (same = false)
		{
			cerr << "Attempted assignment to itself" << endl;
		}
	}
	else
	{
		Node* other = lst.first;
		Node* current = first;
		if (first == nullptr)
		{		
			while (other != nullptr)
			{
				insertBack(other->getData());
				other = other->getNext();
			}
		}
		else if (count > lst.count)
		{	
			while (current != nullptr)
			{
				if (other != nullptr)
				{
					current->setData(other->getData());
					other = other->getNext();
					current = current->getNext();
				}
				else
				{
					Node* temp = current;
					current = current->getNext();
					delete temp;
					temp = nullptr;
					--count;
				}
			}
		}
		else if (count == lst.count)
		{
			while (current != nullptr)
			{
				current->setData(other->getData());
				other = other->getNext();
				current = current->getNext();
			}
		}
		else if (count < lst.count)
		{
			while (other != nullptr)
			{
				if (current != nullptr)
				{
					current->setData(other->getData());
					other = other->getNext();
					current = current->getNext();
				}
				else
				{
					insertBack(other->getData());
					other = other->getNext();
				}
			}
		}
		else
		{
			destroyList();
		}
	}

	return *this;
}




And this is the error message I get:
Exception thrown: read access violation.
**this** was 0xFFFFFFFFFFFFFFFF.
Last edited on
ar2007 (210)
can you post the definition of constructor of doublylist class?


DoublyList();
kikiyox77 (50)
This is the default constructor:
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#include "DoublyList.h"

DoublyList::DoublyList()
{
	first = nullptr;
	last = nullptr;
	count = 0;
}
kikiyox77 (50)
This is the DoublyList.cpp:
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#include "DoublyList.h"

DoublyList::DoublyList()
{
	first = nullptr;
	last = nullptr;
	count = 0;
}

void DoublyList::insertBack(int elem)
{
	Node *newNode = new Node(elem, last, NULL);

	if (first == NULL)
		first = newNode;
	else
		last->setNext(newNode);

	last = newNode;
	++count;
}

void DoublyList::insertBack(const int a[], int numOfElem)
{
	for (int i = 0; i < numOfElem; ++i)
		insertBack(a[i]);
}

int DoublyList::getFirst() const
{
	if (first == nullptr)
		return 0;
	else
		return first->getData();
}

int DoublyList::getLast() const
{
	if (first == nullptr)
		return 0;
	else
		return last->getData();
}

int DoublyList::getNumOfElem() const
{
	return count;
}

Node* DoublyList::getPrevOfFirst() const
{
	if (first == nullptr)
		return 0;
	else
		return first->getPrev();
}

Node* DoublyList::getNextOfLast() const
{
	if (first == nullptr)
		return 0;
	else
		return last->getNext();
}

// getFirstNodeAddress
Node& DoublyList::getFirstNodeAddress() const
{
	return *first; // return the address of the node first is pointing to
}

// getLastNodeAddress
Node& DoublyList::getLastNodeAddress() const
{
	return *last; // return the address of the node last is pointing to
}

void DoublyList::reversePrint() const
{
	if (first == nullptr)
		cout << "List is empty.";
	else
	{
		Node *temp = last;

		while (temp != NULL)
		{
			cout << temp->getData() << " ";
			temp = temp->getPrev();
		}
	}
}

void DoublyList::destroyList()
{
	Node  *temp = first;

	while (first != nullptr)
	{
		first = first->getNext();
		delete temp;
		temp = first;
	}

	last = nullptr;
	count = 0;
}

DoublyList::~DoublyList()
{
	destroyList();
}
kikiyox77 (50)
This is the Main.cpp (I am not allowed to change anything in this file, just to let you guys know what all the files had):
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#include "DoublyList.h"

#include <iostream>
using namespace std;

//pass by value to preserve original lists
void testCopyConstructor(DoublyList param, int n);
void testOverloadedAssignment(DoublyList calling, DoublyList param, int n);

int main()
{
	int a0[10];
	int a1[20] = { 45 };
	int a2[30] = { 64, 24 };
	int a4[40] = { 13, 54, 12, 34};
	int a7[10] = { 76, 36, 91, 93, 74, 58, 23 };

	DoublyList list0, list1, list2, list4, list7;

	list0.insertBack(a0, 0);
	list1.insertBack(a1, 1);
	list2.insertBack(a2, 2);
	list4.insertBack(a4, 4);
	list7.insertBack(a7, 7);

	cout << "TEST: COPY CONSTRUCTOR" << endl;
	// Copy constructor: calling (empty) - param (empty)
	testCopyConstructor(list0, 1);							// TEST 1
	// Copy constructor: calling (empty) - param (1)
	testCopyConstructor(list1, 2);							// TEST 2
	// Copy constructor: calling (empty) - param (2)
	testCopyConstructor(list2, 3);							// TEST 3
	// Copy constructor: calling (empty) - param (4)
	testCopyConstructor(list4, 4);							// TEST 4
	// Copy constructor: calling (empty) - param (7)
	testCopyConstructor(list7, 5);							// TEST 5

	cout << endl;

	cout << "TEST: OVERLAODED ASSIGNMENT OPERATOR" << endl;
	// Overloaded assignment operator: calling (empty) - param (empty)
	testOverloadedAssignment(list0, list0, 6);								// TEST 6
	// Overloaded assignment operator: calling (empty) - param (1)
	testOverloadedAssignment(list0, list1, 7);								// TEST 7
	// Overloaded assignment operator: calling (empty) - param (2)
	testOverloadedAssignment(list0, list2, 8);								// TEST 8
	// Overloaded assignment operator: calling (empty) - param (4)
	testOverloadedAssignment(list0, list4, 9);								// TEST 9
	// Overloaded assignment operator: calling (empty) - param (7)
	testOverloadedAssignment(list0, list7, 10);								// TEST 10
	// Overloaded assignment operator: calling (1) - param (empty)
	testOverloadedAssignment(list1, list0, 11);								// TEST 11
	// Overloaded assignment operator: calling (1) - param (1)
	testOverloadedAssignment(list1, list1, 12);								// TEST 12
	// Overloaded assignment operator: calling (1) - param (2)
	testOverloadedAssignment(list1, list2, 13);								// TEST 13
	// Overloaded assignment operator: calling (1) - param (4)
	testOverloadedAssignment(list1, list4, 14);								// TEST 14
	// Overloaded assignment operator: calling (1) - param (7)
	testOverloadedAssignment(list1, list7, 15);								// TEST 15
	// Overloaded assignment operator: calling (2) - param (empty)
	testOverloadedAssignment(list2, list0, 16);								// TEST 16
	// Overloaded assignment operator: calling (2) - param (1)
	testOverloadedAssignment(list2, list1, 17);								// TEST 17
	// Overloaded assignment operator: calling (2) - param (2)
	testOverloadedAssignment(list2, list2, 18);								// TEST 18
	// Overloaded assignment operator: calling (2) - param (4)
	testOverloadedAssignment(list2, list4, 19);								// TEST 19
	// Overloaded assignment operator: calling (2) - param (7)
	testOverloadedAssignment(list2, list7, 20);								// TEST 20
	// Overloaded assignment operator: calling (4) - param (empty)
	testOverloadedAssignment(list4, list0, 21);								// TEST 21
	// Overloaded assignment operator: calling (4) - param (1)
	testOverloadedAssignment(list4, list1, 22);								// TEST 22
	// Overloaded assignment operator: calling (4) - param (2)
	testOverloadedAssignment(list4, list2, 23);								// TEST 23
	// Overloaded assignment operator: calling (4) - param (4)
	testOverloadedAssignment(list4, list4, 24);								// TEST 24
	// Overloaded assignment operator: calling (4) - param (7)
	testOverloadedAssignment(list4, list7, 25);								// TEST 25
	// Overloaded assignment operator: calling (7) - param (empty)
	testOverloadedAssignment(list7, list0, 26);								// TEST 26
	// Overloaded assignment operator: calling (7) - param (1)
	testOverloadedAssignment(list7, list1, 27);								// TEST 27
	// Overloaded assignment operator: calling (7) - param (2)
	testOverloadedAssignment(list7, list2, 28);								// TEST 28
	// Overloaded assignment operator: calling (7) - param (4)
	testOverloadedAssignment(list7, list4, 29);								// TEST 29
	// Overloaded assignment operator: calling (7) - param (7)
	testOverloadedAssignment(list7, list7, 30);								// TEST 30

	cout << endl << endl;
	system("Pause");
	return 0;
}

void testCopyConstructor(DoublyList param, int n)
{
	cout << "TEST: " << n << endl;
	cout << "Parameter list: " << param << endl;

	int param_first = param.getFirst();
	int param_last = param.getLast();
	int param_count = param.getNumOfElem();
	Node* param_getPrevOfFirst = param.getPrevOfFirst();
	Node* param_getNextOfLast = param.getNextOfLast();

	DoublyList temp(param);

	cout << "New list (print forward): " << temp << endl;
	cout << "New list (print reverse): ";
	temp.reversePrint();
	if (param_first != temp.getFirst()) cout 
		<< "*** ERROR ***  First node not storing correct value." << endl;
	if (param_last != temp.getLast()) cout 
		<< "*** ERROR ***  Last node not storing correct value. " << endl;
	if (param_count != temp.getNumOfElem()) cout 
		<< "*** ERROR ***  Number of elements is incorrect." << endl;
	if (param_getPrevOfFirst != temp.getPrevOfFirst()) cout 
		<< "*** ERROR ***  Pointer prev of first node is not NULL." << endl;
	if (param_getNextOfLast != temp.getNextOfLast()) cout 
		<< "*** ERROR ***  Pointer next of last node is not NULL." << endl;
	if (param.getNumOfElem() != 0)
	{
		if (param.getFirstNodeAddress() == temp.getFirstNodeAddress()) cout 
			<< "*** ERROR ***  Both lists are pointing to the same first node." << endl;
		if (param.getLastNodeAddress() == temp.getLastNodeAddress()) cout 
			<< "*** ERROR ***  Both lists are pointing to the same first node." << endl;
	}
	
	cout << endl;
}

void testOverloadedAssignment(DoublyList calling, DoublyList param, int n)
{
	cout << "TEST: " << n << endl;
	cout << "Calling list: " << calling << endl; 
	cout << "Parameter list: " << param << endl;

	int calling_first = calling.getFirst();
	int calling_last = calling.getLast();
	int calling_count = calling.getNumOfElem();
	Node* calling_getPrevOfFirst = calling.getPrevOfFirst();
	Node* calling_getNextOfLast = calling.getNextOfLast();

	int param_first = param.getFirst();
	int param_last = param.getLast();
	int param_count = param.getNumOfElem();
	Node* param_getPrevOfFirst = param.getPrevOfFirst();
	Node* param_getNextOfLast = param.getNextOfLast();

	calling = param;

	cout << "... Call overloaded assignment operator... calling = param" << endl;
	cout << "Calling list (print forward): " << calling << endl;
	cout << "Parameter list (print forward): " << param << endl;
	cout << "Calling list (print reverse): ";
	calling.reversePrint();
	cout << endl;
	cout << "Parameter list (print reverse): ";
	param.reversePrint();
	cout << endl;

	if (param_first != calling.getFirst()) cout 
		<< "*** ERROR ***  First node not storing correct value. (Test " << n << ")" << endl;
	if (param_last != calling.getLast()) cout 
		<< "*** ERROR ***  Last node not storing correct value. (Test " << n << ")" << endl;
	if (param_count != calling.getNumOfElem()) cout 
		<< "ERROR: Number of elements is incorrect. (Test " << n << ")" << endl;
	if (param_getPrevOfFirst != calling.getPrevOfFirst()) cout 
		<< "ERROR: Pointer prev of first node is not NULL. (Test " << n << ")" << endl;
	if (param_getNextOfLast != calling.getNextOfLast()) cout 
		<< "ERROR: Pointer next of last node is not NULL. (Test " << n << ")" << endl;
	if (param.getNumOfElem() != 0)
	{
		if (calling.getFirstNodeAddress() == param.getFirstNodeAddress()) cout 
			<< "ERROR: Both lists are pointing to the same first node. (Test " << n << ")" << endl;
		if (calling.getLastNodeAddress() == param.getLastNodeAddress()) cout 
			<< "ERROR: Both lists are pointing to the same first node. (Test " << n << ")" << endl;
	}

	cout << endl;
}
kikiyox77 (50)
Can anyone help me with this? I have provided all files that were part of the project.
I need help with the overloaded insertion operator and the copy constructor
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