Linked List code not compiling

[gkropp]

I've inherited some legacy code that I need to modify. The code that needs to be modified uses Linked Lists. I'm familiar with the concept of linked lists and used them extensively in the distant past but not in C++.

The code I need to modify manages a linked list that has 4 linked lists as data elements. The 4 sub lists are synchronized with each other - the first elements in each sub list go together, the second elements in each sub list go together, the third elements in each sub list go together, etc. There is no set number of nodes possible for the sub lists, but they must all be the same length.

A 5th data type has been added to each set, which means I need a 5th sub list. After all of nodes in all of the linked lists have been populated, I have to go back and perform math on the data contained in two of the lists based on the value in the new 5th list (which is based on an enumeration) and then put the result back into the 1st list.

Here's the basic format:
- Main List
-- Sub List 1 - data
-- Sub List 2 - data
-- Sub List 3 - data
-- Sub List 4 - data
-- Sub List 5 - data type (enumeration)

I've got two problems I need help with: (1) how to correctly read the value contained in SL5, and (2) how to put the data back into a node in SL1.

I want to be able to do the above without writing my own linked list management routines.

Here's an example of my code (I can't give the actual code because of the nature of the project).

DataTypeEnum		firstDataTypeA;
double			tempDataType1;
double			tempDataType2;
double			tempDataType3;
int			numNodes;
LinkedList*             tempList;

for (int x=0; x,numNodes; x++)
{
	//I need help here, because this gives me a data exception at runtime
	firstDataTypeA = *(( DataTypeEnum)tempList->tempExtraData.dataTypeA->GetPointer(x));
	if (firstDataTypeA = DataTypeEnumOne)
	{
		tempDataType1 = *((double) tempList->tempExtraData.dataType1->GetPointer(x));
		tempDataType2 = *((double) tempList->tempExtraData.dataType2->GetPointer(x));
		tempDataType3 = tempDataType1/ tempDataType2;
		
		//This is where I can't get the syntax correct.  I know the below isn't correct, but it is 			
                // logically what I want to do.  I've tried many different combinations of indirection, etc.
                //"currentnode" is not an actual piece of code...it's a place holder to help explain what I want to do
		tempList->tempExtraData.dataType1.currentnode = tempDataType3;
		tempList->tempExtraData.dataTypeA.currentnode = DataTypeEnumTwo;
	}
}

So, as I stated earlier I need help with
1. Reading an enumeration value from a node in a linked list (line 11).
2. How to change a value in a node without rebuilding the whole sub list (lines 21 & 22).

For #2, I think it has to do with indirection and/or pointing to the address of the node, I just haven't been able to get the syntax right so that I can get it to compile.

Some additional details: we are using VS2005 on Win XP. I do not have the option of upgrading either VS2005 or using a different OS.

Thanks,

gk

[gkropp]

I resolved my first question..."Reading an enumeration from a node in a linked list". In the original declaration of the linked list, I left out one level of indirection. Once I put that in, it worked.

I'm still struggling with lines 21 & 22. The options I have for "currentnode" are GETPOINTER, APPEND, POPOFF, LENGTH, NEXT and HEAD.

So if anyone has an idea how to assign a value back to a node it would be greatly appreciated.

gk