while(choix != '6')
    {
    choix = lire_menu('1','6');
    switch(choix)
        {
        case '1': ajout_adherent(adhr, n_adhr);
            break;
        case '2': modif_adherent(adhr, n_adhr);
            break;
        case '3': supprime_adherent(adhr, n_adhr, livres, n_livres);
            break;
        case '4': liste_adherents(adhr, n_adhr);
            break;
        case '5': recherche_adherent(adhr, n_adhr);
            break;
        default : break;
        }

    }
};