Stack around the variable 'n' was corrupted? C++ VS2010 - c++

Question

So I'm working on a college project where I need to create a linked list of 'Structures'. and when I'm adding a new element to the linked list I get this error, which is weird because I am not even using the stack while doing it.
Here's how 'Structure' is defined:
#ifndef Structure_h
#define Structure_h
#include <stack>
using namespace std;
class Structure
{
public:
int Integer;
stack <int> s;
};
#endif
Definition of node:
#pragma once
#ifndef Node_h
#define Node_h
using namespace std;
#include "Structure.h"
class Node
{
public:
Node();
Structure Str;
Node *next;
};
#endif
LinkedList.h:
#pragma once
#ifndef LinkedList_h
#define LinkedList_h
using namespace std;
#include "Node.h"
class LinkedList
{
public:
LinkedList();
int size;
void add(int a);
Node *Current;
Node *Start;
};
#endif
LinkedList.cpp:
#include "LinkedList.h"
#include <iostream>
LinkedList::LinkedList()
{
Node FirstNode;
Start = Current = &FirstNode;
cout << "Start = " << Start->Str.Integer << endl;
cout << "Current = " << Current->Str.Integer << endl;
}
void LinkedList::add(int a)
{
Node n;
n.Str.Integer = a;
Current->next = &n;
Current = Current->next;
cout << Current->Str.Integer;
}
Now whenever I create a new LinkedList and adding something to it I get this error.
I got a feeling like I'm using the Stack wrong somehow, not sure why though.
Thank you from advance.

Answer 1

In this method:
void LinkedList::add(int a)
{
Node n;
n.Str.Integer = a;
Current->next = &n;
Current = Current->next;
cout << Current->Str.Integer;
}
you are adding as next local variable n, it will get destroyed once add returns. This is undefined behaviour. You should use Node* n = new Node;, dont forget to deallocate.
[edit]
The same applies to other places in your code where you take a pointer to local variable and store it as a list node.

Answer 2

You have:
void LinkedList::add(int a)
{
Node n;
n.Str.Integer = a;
Current->next = &n;
// Here, you are storing a pointer to a local variable.
// The pointer becomes a dangling pointer when the function returns.
Current = Current->next;
cout << Current->Str.Integer;
}
Use a dynamically allocated Node.
void LinkedList::add(int a)
{
Node* n = new Node;
n->Str.Integer = a;
Current->next = n;
Current = Current->next;
cout << Current->Str.Integer;
}