Linked Numbers

#include <bits/stdc++.h>
using namespace std;


struct Node {
    Node *next;
    int data;
};


class LinkedList{
    public:
    LinkedList(){
        head = nullptr;
        tail = nullptr;
    }
    ~LinkedList(){
        Node* temp;
        while(head != nullptr){
            temp = head;
            head = head->next;
            delete temp;
        }
    }
    void add(int value){
        Node* temp = new Node;
        temp->data = value;
        temp->next = nullptr;

        if (head == nullptr and tail == nullptr){
            head = tail = temp;
        } else {
            tail->next = temp;
            tail = temp;
        }
    }
    void print(){
        Node* curr = head;
        while(curr != nullptr){
            cout << curr->data << " ";
            curr = curr->next;
        }
    }

    Node* getHead(){
        return head;
    }

private:
    Node *head, *tail;
};

void solve(LinkedList& num1, LinkedList& num2){
    Node* curr1 = num1.getHead();
    Node* curr2 = num2.getHead();
    stringstream res;
    int prev = 0;
    while(curr1 && curr2){
        int sum = curr1->data + curr2->data + prev;
        res << (sum % 10);
        prev = sum / 10;

        curr1 = curr1->next;
        curr2 = curr2->next;
    }

    while(curr1){
        res << (curr1->data + prev) % 10;
        prev = (curr1->data + prev) / 10;
        curr1 = curr1->next;
    }
    while(curr2){
        res << (curr2->data + prev) % 10;
        prev = (curr2->data + prev) / 10;
        curr2 = curr2->next;
    }

    if(prev != 0)
        res << prev;
    string result;
    res >> result;
    reverse(result.begin(), result.end());
    cout << result;
}

int main(){
    LinkedList num1, num2;

    int size1, size2;
    cin >> size1;
    for(int i = 0 ; i < size1 ; i++){
        int digit;
        cin >> digit;
        num1.add(digit);
    }

    cin >> size2;
    for(int i = 0 ; i < size2 ; i++){
        int digit;
        cin >> digit;
        num2.add(digit);
    }

    solve(num1, num2);
}