Ytdyklly

I created a linked list in C++ using class with few methods to provide interface for it.

Methods are pushFront(), traverse() and few more as shown below. PushFront is used to insert the data at the head of linked list at any given time. traverse is to display the linked list at any time. My code is shown below:

#include <iostream>

using namespace std;

class SingleLL{

    private:

    struct Node

    {

        int data;

        Node * next;

    };

    Node * head;

    Node * tail;

    public:

    SingleLL();

    void pushFront(int i);

    int topFront(); 

    void popFront();

    void pushBack(int i);

    int topBack();

    void popBack();

    bool find(int key);

    void erase(int key);

    void addBefore(int beforekey,int key);

    void addAfter(int afterkey,int key);

    bool empty();

    void traverse();

};

SingleLL::SingleLL(){

     head = nullptr;

     tail = nullptr;

}

void SingleLL::pushFront(int i)

{

    Node * newNode =new Node;

    newNode->data=i;

    newNode->next=head;

    head=newNode;

    if(tail==nullptr)

        tail = head;

}

int SingleLL::topFront()

{

    if(empty())

    {

        cout<<"No element at the front top.n";

        return 0;

    }

    return head->data;

}

void SingleLL::popFront()

{

    if (empty()){

        cout<<"No element to pop.n";

        return;

    }

    head=head->next;

    if(head==nullptr)

        tail=nullptr;

}

void SingleLL::traverse()

{

    if (empty())

        cout<<"empty list. add elements";

    Node * ptr =  head;

    while(ptr!=nullptr)

    {

        cout<<ptr->data;

        ptr=ptr->next;

    }

}

bool SingleLL::empty()

{

    return head==nullptr;

}

int SingleLL::topBack()

{

    if(empty())

    {

        cout<<"No element at the back top.n";

        return 0;

    }

    return tail->data;

}

void SingleLL::popBack()

{

    if(empty()){

        cout<<"No element to popn";

        return;

    }

    Node *ptr=head;

    if(head->next==nullptr)

    {

        head=nullptr;

        tail=nullptr;

    }

    while(ptr->next->next != nullptr)

    {

        ptr=ptr->next;



    }

    tail=ptr;

    ptr->next=nullptr;

}

void SingleLL::pushBack(int i)

{

    Node * newNode2 =new Node;

    newNode2->data=i;

    newNode2->next=nullptr;

    if(tail!=nullptr)

        tail->next=newNode2;

    tail=newNode2;

    if(head==nullptr)

        head=tail;





}

bool SingleLL::find(int key)

{

    if(head == nullptr)

        return false;

    Node * boolfinder = head;



    while(boolfinder->next!=nullptr)

    {

        if(boolfinder->data==key)

        {

            return true;

        }

        boolfinder=boolfinder->next;



    }

    return false;

}

void SingleLL::erase(int key)

{

    if(find(key))

    {

        if (head->data==key)

        {

            popFront();

            return;

        }

        if(tail->data==key)

        {

            popBack();

            return;

        }

        Node * finderprev = head;

        Node * findererase = head->next;

        while(findererase!=nullptr)

        {

            if(findererase->data==key)

            {

                finderprev->next=findererase->next;

                free(findererase);

                break;

            }

            findererase=findererase->next;

            finderprev=finderprev->next;

        }

    }

    else

        cout<<"There is no such key to erase";

}

void SingleLL::addAfter(int afterkey,int key)

{

    Node * newNode =new Node;

    newNode->data=key;

    Node * ptr = head;

    while(ptr!=nullptr)

    {

        if(ptr->data==afterkey)

        {

            newNode->next=ptr->next;

            ptr->next=newNode;

            if(newNode->next==nullptr)

                tail=newNode;

            return;

        }

        ptr=ptr->next;

    }



    cout<<"There is no "<<afterkey<<" key to add "<<key<<" key before it.";



}

void SingleLL::addBefore(int keybefore,int key)

{



    if(head->data==keybefore)

    {

        pushFront(key);

        return;

    }

    Node * newNode1 = new Node;

    newNode1->data=key;

    Node *ptr = head->next;

    Node *ptrprev = head;

    while(ptr!=nullptr)

    {

        if(ptr->data==keybefore)

        {

            newNode1->next=ptr;

            ptrprev->next=newNode1;

            return;

        }

        ptr=ptr->next;

        ptrprev=ptrprev->next;

    }

    cout<<"There is no"<<keybefore<<" key to add "<<key<<" key before it.";



    }

int main()

{

    SingleLL l1;

    for(int i=10;i>=1;i--)

        l1.pushFront(i);

    l1.traverse();

    l1.popFront();

    cout<<"n";

    l1.traverse();  

    for(int i=0;i<8;i++)

        l1.popFront();

    cout<<"n";

    l1.traverse();

    l1.popFront();

    l1.popFront();

    l1.popBack();

    if(l1.empty())

        cout<<"linked list is empty.n";

    l1.topBack();

    l1.popBack();

    return 0;

}

I know that many things that I have used is not upto mark, like I have used struct like in old c where it contains data only. I have seen implementation of linked list using class in few other languages like java and python. But since C++ takes many or we can say all features from c language and adds O.O.P.to that, there are many things different in this language. Can anyone provide me the valuable code review and point out what are the things that I need to improve in my coding style. And how can I improve my O.O.P. design skills. What are the mistakes in this code? And also what changes should I do to make it full modern powerful C++ code?
And even though I will try it myself anyways i need valuable insight from this community on how to templatize or make this class generic so that it takes any atomic data type not only integer type as it does now.