Linked List Front() function syntax error

Question

I am trying to return a Node in my Front() method of my linked list class. The front method just returns the first element in the linked list (i.e. which is a node). The compiler does not like this, however. It gives me the following error.

Error: initial reference value of reference to non-const must be an lvalue.

Does anyone know a way around this?? mHead is what is underlined by intellisense.

Node &List::Front()
{
return mHead->getData();
}

Potion Node::getData()
{
return mData;
}

list.h

#ifndef LIST_H
#define LIST_H

#include "node.h"
#include "potion.h"

class List
{

public:
//Default constructor
List();

//Copy constructor
List(const List & copy);

//Overloaded assignment operator
List &operator=(const List & rhs);

//Destructor
~List();

//Methods
void PushFront(Node * newNode);
void PushBack(Node * newNode);
void PopFront();
void PopBack();
/*const Potion &Front() const;
const Potion &Back() const;*/
Node &Front();
Node &Back();
void Purge();
bool empty();
int getNumberOfNodes();
Node * CreateNode(Potion potion);
void Save(std::ofstream & file);
void Load(std::ifstream & file);

protected:
//Data members
Node * mHead;
Node * mTail;
static int mNumberOfNodes;
};

#endif

Shouldn't that be return *mHead;? You want to return a Node not a Potion. — Jesse Good
– Jesse Good, Commented May 7, 2013 at 20:53

Mark Ransom · Accepted Answer · 2013-05-07 20:51:24Z

3

I'd guess that your getData() function is returning a copy of the data rather than a reference. A temporary object isn't an lvalue.

answered May 7, 2013 at 20:51

Mark Ransom

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2 Comments

MrPickle5 Over a year ago

I just changed it to return by reference and now it is saying error: a reference of type "Node &" (not const-qualified) cannot be initialized with a value type of Potion

Mark Ransom Over a year ago

@MrPickle5, your signature says you're returning Node& but you're trying to return a Potion&. You need to pick one or the other and be consistent.

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