add: cout << "result = " << calc.eval.top() << endl;
context: main(){    cout << "/////////////////////////////////////////////////////////\n\n";    cout << "\t\tExpression parser...\n\n";    cout << "/////////////////////////////////////////////////////////\n\n";    cout << "Type an expression...or [q or Q] to quit\n\n";    calculator calc;    //  Our parser    string str;    while (getline(cin, str))    {        if (str[0] == 'q' || str[0] == 'Q')            break;        parse_info<> info = parse(str.c_str(), calc, space_p);        if (info.full)        {            cout << "-------------------------\n";            cout << "Parsing succeeded\n";            cout << "-------------------------\n";        }        else        {            cout << "-------------------------\n";            cout << "Parsing failed\n";            cout << "stopped at: \": " << info.stop << "\"\n";            cout << "-------------------------\n";        }    }    cout << "Bye... :-) \n\n";    return 0;}