Palindrome Numbers with string addition

#include <iostream>
#include <algorithm>
#include <string>
#include <conio.h>

using namespace std;

string bnm_add(string a, string b)
{
    string wynik;
    string length;                          // length == najdｳuｿszy string
    int aln, bln, switcher(0);              // switcher -> dodaje 1 w lewej komce, gdy 199 + 001 = 19: -> 1:0 -> 200
    aln = a.length();
    bln = b.length();
    //printf("\na: %i \nb: %i\n\n", aln, bln);
    if (aln > bln)
    {                                       //DODAWANIE ZER : 199 + 1 -> 199 + 001 = 200, (aby 199 + 1 != 299)
        length = a;
        reverse(b.begin(), b.end());
        while (true)
        {
            b += '0';
            bln++;
            if (bln == aln)break;
        }
        reverse(b.begin(), b.end());                // odwracamy 1 -> 100 -> 001 itd.
    }
    else if (bln > aln)
    {
        length = b;
        reverse(a.begin(), a.end());
        while (true)
        {
            a += '0';
            aln++;
            if (aln == bln)break;
        }
        reverse(a.begin(), a.end());
    }
    else if (aln == bln)
    {
        length = a;
    }
    for (size_t x = length.length() - 1; x >= 0; x--)
    {
        char buffor;
        buffor = a[x] + (b[x] - 48) + switcher; // Wstawianie do bufora wartosci, np. 1 + 2 (buff = 49 + (50-48) + 0)
        if (buffor < 48)
        {
            buffor += 48;
        }
        switcher = 0;
        if (buffor > 57)                                // przypadek np. 96 + 85
        {
            switcher = 1;
            buffor -= 10;
        }
        wynik += buffor;                                // dodawanie buffora do wyniku
        buffor = { 0 };
        if (x == 0 && switcher == 1)
        {
            wynik += '1';                               // Przechodzenie np. 9 -> 10, 999 -> 1249, dodawanie jedynki po lewej.
        }
        if (x == 0)break;
    }
    reverse(wynik.begin(), wynik.end());            // na koniec odwracamy (wszystko byｳo odwrotnie naliczane)
    //printf("\n  %s\n+ %s\n____________________________________________________\n  %s\n\n", a.c_str(), b.c_str(), wynik.c_str());
    return wynik;
}

class zliczanie
{

    bool if_number = false;
    bool czy_palindrom = false;
    string buff, nbuff, i1npocz;
    long long lit = 0;
    string pocz, npocz;
public:
    bool lel = true;

    void wprowadzanie()
    {
        cout << endl;
        buff.clear();
        cin >> buff;
        cout << endl;
        for (size_t i = 0; i < buff.length(); i++)
        {
            if (buff[i] == '0' || buff[i] == '1' || buff[i] == '2' || buff[i] == '3' || buff[i] == '4' || buff[i] == '5' || buff[i] == '6' || buff[i] == '7' || buff[i] == '8' || buff[i] == '9')
            {
                if_number = true;
            }
            else
            {
                if_number = false;
                cin.clear();
                cout << "GIVE A NUMBER!" << endl;
                return wprowadzanie();
            }
        }
    }
    void check()
    {
        while (czy_palindrom == false)
        {
            if (lit == 0)
            {

                string a = buff;
                pocz = a;
                nbuff = buff;
                reverse(nbuff.begin(), nbuff.end());
                string b = nbuff;
                npocz = b;
            }
            if (lit > 1000)
            {
                cout << "Value your computer and give another number ;) " << endl;
                lel = false;
                break;
            }
            if (nbuff == buff)
            {
                czy_palindrom = true;
                lel = false;
                break;
            }
            else
            {
                buff = bnm_add(buff, nbuff);
                //cout << endl << "buff: " << buff << endl;
                lit++;
                nbuff = buff;
                reverse(nbuff.begin(), nbuff.end());
                if (lit == 1)
                {
                    i1npocz = nbuff;
                }
                return check();
            }
        }
    }
    void wynik()
    {
        if (czy_palindrom == true)
        {
                cout << endl << "Number " << pocz << " after " << lit << " iterations is a palindrome: " << buff << endl << endl;
        }
    }
};

int main()
{
    zliczanie a1;

    a1.wprowadzanie();
    while (a1.lel == true)
    {
        a1.check();
    }
    a1.wynik();
    cout << "click 'r' to continue" << endl;
    char t = _getch();
    if (t == 'r')
    {
        cout << endl << endl << "_______" << endl;
        return main();
    }
    else
    return 0;
}