Access violation writing location

[mattm86]

I am getting an access violation writing location on line 267. The first document it read has the numbers 1 - 100. The second document is blank. It is checking to see if 1 is odd and then placing it in the odd doubly linked list. As soon as it gets to line 267 its giving me a Access violation writing location. I have verified val is indeed an int of 1. It is also giving me the same error when i try to add an even number to the even doubly linked list. Any help would be much appreciated. A side not is this is for a class and we cannot use any class's or OOP.

#include <iostream>
#include <iomanip>
#include <string>
#include <cstdlib>
#include <stack>
#include <fstream>
#include <cmath>
using namespace std;

// -- Even doubly link list ------------------------------------
struct evenLink {
	evenLink *prev;
	int integer;
	evenLink *next;
};

struct evenInfo {
	evenLink *top;
	int length;
};
// -------------------------------------------------------------

// -- Odd doubly link list -------------------------------------
struct oddLink {
	oddLink *prev;
	int integer;
	oddLink *next;
};

struct oddInfo {
	oddLink *top;
	int length;
};
// -------------------------------------------------------------

// -- GLOBAL CONST ---------------------------------------------
const string FILE_ONE_ERROR = "Please enter a valid first file: ";
const string FILE_TWO_ERROR = "Please enter a valid second file: ";
const string EVEN_COUNT = " integers inserted into Even list:";
const string ODD_COUNT = " integers inserted into Odd list:";
const int ONE = 1;
const int TWO = 2;
// -------------------------------------------------------------

// -- EVEN ADT -------------------------------------------------
bool EmptyListEven(evenInfo *newStack);
int ListLengthEven(evenInfo *newNode);
void DisplayListEven(evenInfo *newStack);
void OrderedListInsertionEven(int val, evenInfo *newList);
// -------------------------------------------------------------

// -- ODD ADT --------------------------------------------------
bool EmptyListOdd(oddInfo *newStack);
int ListLengthOdd(oddInfo *newNode);
void DisplayListOdd(oddInfo *newStack);
void OrderedListInsertionOdd(int oddVal, oddInfo *newList);
// -------------------------------------------------------------

// -- Prototype ------------------------------------------------
void openFile(int fileNum, string fileError, ifstream& file, char* argv[]);
void InitializeList(evenInfo *newEven, oddInfo *newOdd);
void ReadFile(ifstream& file, oddInfo *oddList, evenInfo *evenList);

// -------------------------------------------------------------


int main(int argc, char* argv[])
{
	ifstream file1;						//file input 1 from command line
	ifstream file2;						//file input 2 from command line
	evenInfo *newEven;						//node to be initialized for even link
	oddInfo *newOdd;						//node to be initialized for odd link
	bool evenEmpty;
	bool oddEmpty;
	int evenLength;
	int oddLength;

	newOdd = new oddInfo;
	newEven = new evenInfo;

	openFile(ONE, FILE_ONE_ERROR, file1, argv);
	openFile(TWO, FILE_TWO_ERROR, file2, argv);
	InitializeList(newEven, newOdd);

	evenEmpty = EmptyListEven(newEven);
	evenLength = ListLengthEven(newEven);

	oddEmpty = EmptyListOdd(newOdd);
	oddLength = ListLengthOdd(newOdd);

	ReadFile(file1, newOdd, newEven);

	cout << "Lists created using input file " << argv[1] << endl;
	DisplayListEven(newEven);
	DisplayListOdd(newOdd);

	system("PAUSE");
	return 0;
}


void openFile(int fileNum, string fileError, ifstream& file, char* argv[])
{
	file.open(argv[fileNum]);	     //first file to read
	string fileName;				//string for first file name

	//check the  file is valid
	while (!file){
		cout << "ERROR: Could not locate file" << endl;
		cout << fileError;
		cin >> fileName;
		file.open(fileName);
	}//end if
	//check the second file is valid

	return;

}

void InitializeList(evenInfo *newEven, oddInfo *newOdd)
{
	//Initializes odd node and check for memeory allocation
	newOdd = new oddInfo;
	if (newOdd == NULL){
		cout << "ERROR: Unable to allocate memory for queue." << endl;
	} //end if
	else {
		newOdd->top = NULL;
		newOdd->length = 0;
	} //end else
	//Initializes even node and check for memeory allocation
	newEven = new evenInfo;
	if (newEven == NULL){
		cout << "ERROR: Unable to allocate memory for queue." << endl;
	} //end if
	else {
		newEven->top = NULL;
		newEven->length = 0;
	} //end else

}


bool EmptyListEven(evenInfo *newStack)
{
	return(newStack->top == NULL);
}


bool EmptyListOdd(oddInfo *newStack)
{
	return(newStack->top == NULL);
}


int ListLengthEven(evenInfo *newNode)
{
	return(newNode->length);
}


int ListLengthOdd(oddInfo *newNode)
{
	return(newNode->length);
}


void DisplayListEven(evenInfo *newStack)
{
	int count = 0;

	cout << newStack->length << EVEN_COUNT;

	while (newStack->top != NULL) {
		if (count < 10){
			cout << setw(4) << newStack->top->integer;
			count++;
		}//end if
		else{
			cout << setw(4) << newStack->top->integer;
			count = 0;
		}//end else
	}//end while

}


void DisplayListOdd(oddInfo *newStack)
{
	int count = 0;

	cout << newStack->length << ODD_COUNT;

	while (newStack->top != NULL) {
		if (count < 10){
			cout << setw(4) << newStack->top->integer;
			count++;
		}//end if
		else{
			cout << setw(4) << newStack->top->integer;
			count = 0;
		}//end else
	}//end while

}

void ReadFile(ifstream& file, oddInfo *oddList, evenInfo *evenList)
{
	int readVal = 0;				//value read from file

	//primes file to be read
	file >> readVal;
	//while recieptFile still holds information keep reading
	while (file) {

		if ((readVal % 2) == 0){
			OrderedListInsertionEven(readVal, evenList);

		}//end if

		else {
			OrderedListInsertionOdd(readVal, oddList);

		}//end else

		file >> readVal;
	}//end while
}

void OrderedListInsertionEven(int val, evenInfo *newList)
{

	evenInfo *newNode;                // pointer to create each node

	newNode = new (nothrow)evenInfo; // allocate memory for 1st node 

	if (newNode == NULL)
		cout << "Memory allocation error -- cannot continue" << endl;
	else {
		newList->length++;
		newNode->top->prev = NULL;         // next and prev pointers are set to NULL
		newNode->top->next = NULL;         // since it is the only node

		newNode->top->integer = val;
		newNode->top->prev = NULL;
		newNode->top->next = newList->top;
		if (newList->top != NULL)
			newList->top->prev = newNode->top;
		newList = newNode;
	}
}

void OrderedListInsertionOdd(int val, oddInfo* newList)
{

	oddInfo *temp;                // pointer to create each node

	temp = new (nothrow)oddInfo; // allocate memory for 1st node 

	if (temp == NULL)
		cout << "Memory allocation error -- cannot continue" << endl;
	else {
		newList->length++;
		temp->top = NULL;         // next and prev pointers are set to NULL

		temp->top->integer = val;
		temp->top->prev = NULL;
		temp->top->next = newList->top;
		if (newList->top != NULL)
			newList->top->prev = temp->top;
		newList = temp;
	}
}

[AbstractionAnon]

Line 265: You set temp->top to NULL.
Line 267-269: You now try to dereference this null pointer.

[mattm86]

If i comment out line 265 i get an error Access violation writing location 0xCDCDCDD1 when i hit line 267.

[mattm86]

So it looks like my issue was i was wanting to create a new node call oddLink *temp not oddInfo *temp. This allowed me to do what i was wanting to do. Now when i am setting the newList->top->prev to temp its giving me another allocation error.

void OrderedListInsertionOdd(int val, oddInfo* newList)
{

	oddLink *temp;                // pointer to create each node

	temp = new oddLink; // allocate memory for 1st node 

	if (temp == NULL)
		cout << "Memory allocation error -- cannot continue" << endl;
	else {
		newList->length++;
		//temp->top = NULL;         // next and prev pointers are set to NULL

		temp->integer = val;
		temp->prev = NULL;
		temp->next = newList->top;
		if (newList->top != NULL){
			newList->top->prev = temp;
		}
		newList->top = temp;
	}
}

I should be able to set the pointer for newList->top->prev to temp but i am getting an allocation error. Doubly linked list are also new to me.