Linked List questions

I'm having trouble with a linked list. I keep getting a seg fault when I hit the del function. I'm not sure if my linked list is bad, or if my del function is bad... or if it's the destructor.

Any help is appreciated!!!

app.cpp:

Code:

---

#include <iostream>
#include "linkedlist.h"


using namespace std;


void find(LinkedList& list, char ch)
{
        if (list.find(ch))
                cout << "found ";
        else
                cout << "did not find ";
        cout << ch << endl;
}


int main()
{
    LinkedList      list;


    list.add('x');
    list.add('y');
    list.add('z');
    cout << list;
    find(list, 'y');


    list.del('y');
    cout << list;
    find(list, 'y');


    list.del('x');
    cout << list;
    find(list, 'y');


    list.del('z');
    cout << list;
    find(list, 'y');


    return 0;
}

---

linkedlist.h:

Code:

---

#ifndef _LINKED_LIST_#define _LINKED_LIST_


#include <ostream>


class LinkedList
{
public:
        LinkedList();
        ~LinkedList();


        void add(char ch);
        bool find(char ch);
        bool del(char ch);


        friend std::ostream& operator<<(std::ostream& out, LinkedList& list);


private:
    char letter; //spot to store our letter
    LinkedList *next; //pointer to next list elemenent


};


#endif // _LINKED_LIST_

---

linkedlist.cpp:

Code:

---


#include "linkedlist.h"
using namespace std;


//default data constructor
LinkedList::LinkedList()
{
    //initialize letters pointer to null
    letter = '\n';
    next = nullptr;
}


//default destructor
LinkedList::~LinkedList()
{
    LinkedList *forward = nullptr;
    LinkedList *current = this;
    //iterate through list, deleting each element as we go
    while (current != nullptr)
    {
            //set next pointer to current's next
            forward = current->next;
            delete current; //delete the current memory
            current = forward; //reset current to next's pointer
    }
}


//FUNCTION - add letter (single) to letters list
void LinkedList::add(char ch)
{
    LinkedList *current = this;
    LinkedList *prev = nullptr;
    LinkedList *new_node = new LinkedList();
    if (current == nullptr) //check if it's first item in the list
    {
        new_node->letter = ch;
        new_node->next = nullptr;
        current = new_node;
        return;
    }
    while (current != nullptr)
    {
        prev = current;
        current = current->next;
    }


    new_node->letter = ch;
    new_node->next = nullptr;
    prev->next = new_node;
    return;
}


//FUNCTION - find a letter in our letters list
bool LinkedList::find(char ch)
{
    LinkedList *temp = this;
    while (temp != nullptr)
    {
        if (temp->letter == ch) //if ch is found in our list, return true
            return true;
        else
            temp = temp->next;
    }
    return false; //if ch is not found
}


//FUNCTION - //delete a letter from our letters list
bool LinkedList::del(char ch)
{
    LinkedList *current = this;
    LinkedList *previous = nullptr;


    if (current == nullptr) //if current is empty
        return false;
   
    if (current->letter == ch) //if the first spot is the correct spot to delete
    {
        previous = current;
        current = current->next;
        delete previous;
        return true;
    }
   
    while (current->letter != ch && current != nullptr) //find spot to delete at
    {
        previous = current;
        current = current->next;
    }
    if (current == nullptr) //it didn't find the ch
        return false;
    else
    {
        if (current->next == nullptr) //if at end of list
        {
            previous->next = nullptr;
            delete current;
            return true;
        }
        else
        {
            previous->next = current->next;
            delete current;
            return true;
        }
    }
}
   
//overload friend << operator
std::ostream& operator<<(std::ostream& out, LinkedList& list)
{
    LinkedList *temp = &list;
    while (temp != nullptr)
    {
        out << temp->letter;
        temp = temp->next;
    }
    out << endl;
    return out;
}

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What am I doing wrong??
So far, with the code I have here, I get the first three letters added and printed out, then it hangs up on the del function it appears. I'm thinking it's something to do with the destructor...but I'm not sure.

I should also point out, I'm not to change anything in the main function. Only the linkedlist.cpp file and the private variables in the linkedlist.h file.

Your basic design is seriously flawed. It doesn't really make sense. Look at this:

Code:

---

void LinkedList::add(char ch)
{
    LinkedList *current = this;
    // ...
    if (current == nullptr) //check if it's first item in the

---

Do you really think that this will ever be nullptr? How could you have called a member function with a null this pointer?

Instead you should have a List class and a Node class.

Code:

---

struct Node
{
    char  data;
    Node* next;
 
    Node(char d, Node* n = nullptr) : data(d), next(n) {}
};
 
class List
{
    Node *head = nullptr;
    Node *tail = nullptr;
public:
    List() = default;
    ~List() { clear(); }
    void clear()
    {
        while (head)
        {
            auto to_del = head;
            head = head->next;
            delete to_del;
        }
        tail = nullptr;
    }
    void insert(char data)
    {
        auto node = new Node(data);
        if (tail)
            tail->next = node;
        else
            head = node;
        tail = node;
    }
    void print() const
    {
        for (auto node = head; node; node = node->next)
            std::cout << node->data << ' ';
        std::cout << '\n';
    }
};

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