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Errors with Circular List Program.

Syre Lancaster (8)
Hello. I'm having a bit of trouble with my code.I have worked through most of the issues but I could use a little help. I've been troubleshooting this program for awhile now and I think a set of fresh eyes would help here.

I currently am using CodeBlocks IDE.
Here's my build messages that I get when I try to compile this code:

C:\Users\---\Documents\C++\CCISProject4\main.cpp||In member function 'void CircularLinkedList<ItemType>::printList()':|
C:\Users\---\Documents\C++\CCISProject4\main.cpp|155|error: missing template arguments before '*' token|
C:\Users\---\Documents\C++\CCISProject4\main.cpp|155|error: 'current' was not declared in this scope|
C:\Users\---\Documents\C++\CCISProject4\main.cpp|155|error: 'head' was not declared in this scope|
||=== Build finished: 3 errors, 0 warnings (0 minutes, 0 seconds) ===||

Can anyone point me to what I'm doing wrong here?
Code:

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#ifndef CIRCULARLINKEDLIST_H
#define CIRCULARLINKEDLIST_H
#include <iostream>
#include <string>
using namespace std;

template <class ItemType>
struct nodeType;

template <class ItemType>
class CircularLinkedList
{
	private:
		nodeType <ItemType> *listData;
		int length;
		nodeType <ItemType> *currentPos;

	public:
		CircularLinkedList()
		{
			length = 0;
			listData = NULL;
		}

		~CircularLinkedList()
		{
			makeEmpty();
		}

		CircularLinkedList(const CircularLinkedList<ItemType> &);
		bool operator = (CircularLinkedList<ItemType>);
		bool operator == (CircularLinkedList<ItemType>);
		void operator < (CircularLinkedList<ItemType>);
		void operator > (CircularLinkedList<ItemType>);
		bool isFull() const;
		int getLength() const;
		void retrieveItem(ItemType& item, bool& found);
		void insertItem(ItemType item);
		void deleteItem(ItemType item);
		void resetList();
		void printList();
		void makeEmpty();
		void getNextItem(ItemType &item);
};
#endif

template <class ItemType>
void CircularLinkedList<ItemType>::makeEmpty()
{
	nodeType<ItemType>* tempPtr;

	while (listData != NULL)
	{
		tempPtr = listData;
		listData = listData->next;
		delete tempPtr;
	}
	length = 0;
}

template <class ItemType>
void CircularLinkedList<ItemType>::retrieveItem(ItemType& item, bool& found)
{
	nodeType<ItemType>* location;

	location = listData;
	found = false;

	while( (location != NULL && !found))
	{
		if(item == location->info)
		{
			found = true;
			item = location->info;
		}
		else
			location = location->next;
	}
}

template <class ItemType>
void CircularLinkedList<ItemType>::insertItem(ItemType newItem)
{
	nodeType<ItemType>* location;

	location = new nodeType<ItemType>;
	location->info = newItem;
	location->next = listData;
	listData = location;
	delete location;
	length++;
}

template <class ItemType>
void CircularLinkedList<ItemType>::deleteItem(ItemType item)
{
	nodeType<ItemType>* location = listData;
	nodeType<ItemType>* tempLocation;

	if(item == listData->info)
	{
		tempLocation = location;
		listData = listData->next;
	}
	else
	{
		while(!(item == (location->next)->info))
			location = location->next;

		tempLocation = location->next;
		location->next = (location->next)->next;
	}

	delete tempLocation;
	length--;
}

template <class ItemType>
bool CircularLinkedList<ItemType>::isFull() const
{
	nodeType<ItemType>* ptr;

	ptr = new nodeType<ItemType>;
	if(ptr == NULL)
		return true;
	else
	{
		delete ptr;
		return false;
	}
}

template <class ItemType>
int CircularLinkedList<ItemType>::getLength() const
{
	return length;
}

template <class ItemType>
void CircularLinkedList<ItemType>::resetList()
{
	currentPos = listData;
}

template <class ItemType>
void CircularLinkedList<ItemType>::getNextItem(ItemType &item)
{
	item = currentPos->info;
	currentPos = currentPos->next;
}

template <class ItemType>
void CircularLinkedList<ItemType>::printList()
{
	nodeType* current = head;

	while(current->link != head)
	{
		cout << current->info << " ";
		current = current->link;
	}
	cout << current->info << endl;
}
Last edited on
Danny Toledo (469)
In your printList function you have nodeType* current = head; but nodeType is a class template (which is what the compiler is saying about template arguments).

You also refer to a variable head that doesn't exist. The first instance is here (assuming you fixed the other issue) nodeType<ItemType>* current = head;, did you possibly mean listData instead of head? Or did you forget to create a head node?

The next is in the condition for your while loop, which again should probably be listData (it's hard to say because your naming is non-descriptive).

Making those two changes, I got it to compile but I'll leave it to you to test it.
Syre Lancaster (8)
Do you mind if I ask you what exactly you did to get it to compile? I changed it a bit but now it says:
c:\program files (x86)\codeblocks\mingw\bin\..\lib\gcc\mingw32\4.7.1\..\..\..\libmingw32.a(main.o):main.c:(.text.startup+0xa7)||undefined reference to `WinMain@16'|

These are the changes I made(in bold):

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template <class ItemType>
void CircularLinkedList<ItemType>::printList()
{
	nodeType<ItemType>* current = listData;

	while(current->link != listData)
	{
		cout << current->info << " ";
		current = current->link;
	}
	cout << current->info << endl;
}


Thanks for your help so far.
Last edited on
Danny Toledo (469)
Just add the main function to the end of the code.
Syre Lancaster (8)
Oh right. That totally slipped my mind. 0.o Now I feel like a derp.
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