Thread: Unhandled exception

Hi,
I have already spent some time trying to make work the following code . there is no error message , but an exception instead. the problem seems to come from the fonctions of the class Node and perhaps of the pointer Next which is not well defined.

Code:

#include<iostream>
using namespace std;

class UseNodes
{
private:
	class Node
	{
	public:
		Node()
		{ 
		    Data = 1;
			Next = 0;
		}
		Node(int a):Data(a) {}
		~Node(){};
		Node* GetNext()const{ return Next;}
		void SetNext( Node* A){ Next = A;}
		int GetData()const{ return Data;}
		void setData(int a) { Data = a;}
	private:
		Node* Next;
		int Data;
	};
	Node* Head;
	Node* Tail;

public:
	UseNodes(){Head = 0; Tail = 0; }
	~UseNodes(){};
	void AddNode(int a)
	{
		Node* Temp = new Node(a);
		if(Head==0)
		{
			Head = Temp;
			Tail = Temp;
		}
		else
		{
			Node* Current = new Node();
			Current = Head;
		    while(Current)
			{
				Current = Current->GetNext();
			}
			Current->SetNext(Temp);
			Tail = Temp;
		}
	}
	void Print()const
	{
		int a = 2;
		Node* Temp = new Node(a);
		if(Head==0)
		   cout << " Empty list.\n " ;
		else
		{
			Temp = Head;
			cout << Head->GetData() << endl;
			while(Temp!=Tail->GetNext())
			{				
				cout << Temp->GetData() << endl;
				Temp = Temp->GetNext() ; 
			}
		}
	}

};

int main()
{
	UseNodes A;
	A.AddNode(29);
	A.AddNode(7777);
	A.Print();

	getchar();
}

Thanks for any advice.

The Node* Next member variable is not initialised by the constructor that receives an int argument.

The GetNext function will therefore return an uninitialised pointer.

Assigning Current = Head, leaks the new Node previously assigned to Current.

I guess that the exception comes from the while loop because the GetNext function returns an uninitialised pointer and so you never leave the loop.

Hope this helps....

Where is your return 0?
Code indentation needs adressing a bit

You can get a better explaination of your seg fault if you are using MSVC++ as it will tell you the exact point of the unhandled exception.