bool display(string about)
{
    bool ok = false;
    ifstream file;
    string a;

    file.open(about.c_str());

    if (file.is_open())
    {
        getline(file, a);

        while(a != "X")
        {
            cout << a << endl;
            getline(file, a);
            ok = true;
        }
    }

    else
    {
        cout << "File not found!" << endl;
    }

    return ok;
}

int userInput()
{
    int next;
    bool exit = false;

    cout << endl;
    cout << setw(4) << "7" << setw(4) << "8" << setw(4) << "9" << endl;
    cout << setw(4) << "4" << setw(4) << "5" << setw(4) << "6" << endl;
    cout << setw(4) << "1" << setw(4) << "2" << setw(4) << "3" << endl;
    cout << endl;
    cout << "Please enter a digit (0 to abandon): " << endl;
    cin >> next;

    while (exit == false)
    {
        if ((next >= 0) && (next <= 9))
        {
            exit = true;
        }

        else
        {
            cout << endl;
            cout << "Enter a digit between 0 and 9!" << endl;
            cin >> next;
        }
    }

    return next;
}

#include <iostream>
#include <string>
#include <iomanip>
using namespace std;

int main()
{
   double price;
   int units;
   char dis;
   string fname, nif, adds, pname;

   cout << "Product's price: " << endl;
   cin >> price;

   cout << "Units sold: " << endl;
   cin >> units;

   cout << "Discount (Y/N): " << endl;     //Sí aquí pongo cin.get(dis) se salta
   cin >> dis;                             //esta línea en vez de la de fullname

   cout << "Fullname: " << endl;           //Se salta directamente fullname
   getline(cin, fname);                    //no se por qué

   cout << "NIF: " << endl;
   getline(cin, nif);

   cout << "Address: " << endl;
   getline(cin, adds);

   cout << "Product's name: " << endl;
   getline(cin, pname);

return 0;
}