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What to check for when given 'unresolved externals' error

robertpires (11)
(note: the following CPP file uses a header file provided by the professor that makes the item and node items private members of a Node Class and uses member functions ->getItem(),->getNext(), ->setItem(), and ->setNext() to access them. I didn't want to post the header file in its entirety because I felt it was too much code for one question).

I've been getting unresolved external errors for this CPP file and personally I do not understand what to even look for as everything looks OK to me. I'd like some help in determining what the issue is and what I should generally check when I receive this error in the future.

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 //LinkedSortedList.h File

#ifndef _LINKEDSORTED_LIST
#define _LINKEDSORTED_LIST

#include"Node.h"

template<class ItemType>
class LinkedSortedList
{
private:
	Node<ItemType> *head;
	int itemCount;		//Current count of list items
	//Node<ItemType> *getNodeBefore(const ItemType &anEntry)const;
	Node<ItemType> *getNodeAt(int position) const;
public:
	LinkedSortedList(); //Default constructor
	LinkedSortedList(const LinkedSortedList<ItemType> &aList); //Copy constructor
	bool isEmpty() const; 
	int getLength() const; 
	bool remove(int position); 
	void clear(); //remove all the items from the list
	ItemType getEntry(int position) const; 
	void displayList();

	/*Following are three new methods:
	void insertSorted(const ItemType &newEntry);
	bool removeSorted(const ItemType &anEntry);
	int getPosition(const ItemType &newEntry)const;*/
};

template<class ItemType>
LinkedSortedList<ItemType>::LinkedSortedList (){
	head=NULL;
	itemCount=0;
}

template<class ItemType>
LinkedSortedList<ItemType>::LinkedSortedList(const LinkedSortedList<ItemType> &aList){
	head=aList;
	itemCount=0;
    Node<ItemType> *findItemCount=head;
    (while findItemCount!=NULL){
        findItemCount=findItemCount->getNext();
        itemCount++;
    } 
}

template<class ItemType>
Node<ItemType> *LinkedSortedList<ItemType>::getNodeAt(int position) const{
    if(position<0 || position>itemCount){
        cout<<"Invalid position! Program aborted!\n";
        exit(1);
    }
    Node<ItemType> *nodePtr=head;
      for(int i=1;i<position;i++)
        nodePtr=nodePtr->getNext();
    return nodePtr;
} 

template<class ItemType>
bool LinkedSortedList<ItemType>::isEmpty() const {
	return itemCount==0;
}

template<class ItemType>
int LinkedSortedList<ItemType>::getLength() const {
	return itemCount;
}

template<class ItemType>
bool LinkedSortedList<ItemType>::remove(int position) {
	bool ableToRemove=(position>=1) && (position<=itemCount)
    if(ableToRemove){
        Node<ItemType> *nodePtr=head;
        if(position==1){
            nodePtr=nodePtr->getNext();
            head=nodePtr;
        } else if (position==itemCount) {
        	nodePtr=getNodeAt(position-1);
        	deletePtr=nodePtr->getNext();
        	nodePtr->setNext(NULL);
        	deletePtr=NULL;
            delete deletePtr;
        } else {
        	nodePtr=getNodeAt(position-1);
        	Node<ItemType>* deletePtr = nodePtr->getNext();
        	nodePtr->setNext(deletePtr->getNext());
        	deletePtr=NULL;
            delete deletePtr;
        }
    return ableToRemove;
}

template<class ItemType>
void LinkedSortedList<ItemType>::clear(){
	itemCount=0;
}		

template<class ItemType>
ItemType LinkedSortedList<ItemType>::getEntry(int position) const {
	bool ableToGet=(position>=1) && (position<=itemCount);
    if(ableToGet){
        Node<ItemType> *nodePtr=getNodeAt(position);
        return nodePtr->getItem();
    }
    else
        throw logic_error("You tried to getEntry().....BUT FAILED");
} 

}

template<class ItemType>
void LinkedSortedList<ItemType>::displayList(){
	for(int i=0; i<itemCount; i++)
		cout<<getEntry(i+1)<<endl;
}



#endif


.


ne555 (10692)
if you could provide the error message, that would be great.

http://www.cplusplus.com/forum/general/113904/
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