ToString : convert types to string

Discussion in 'C++' started by Vincent RICHOMME, Jan 27, 2006.

  1. Hi,

    I am developping a software to test smartcard and one of my class is
    shown below :

    class SCardCmd
    SCardCmd(const wxString& strCardName, const wxString& strCmdName):

    const wxString GetCmdName() { return m_strCmdName; }
    const wxString GetCardName() { return m_strCardName; }

    wxString m_strCardName;
    wxString m_strCmdName;
    u8 m_CLA;
    u8 m_INS;
    u8 m_P1;
    u8 m_P2;
    u8 m_Lc;
    u8 m_Data;
    u8 m_Le;
    u8 m_Resp;
    u16 m_SW;

    then I want to display this information but my problem is to convert all
    my values to string.
    What is the better solution :

    1)write a class with static methods to convert types :

    class StrConv

    static std::string StrConv(u8 value) {...;}
    static std::string StrConv(u16 value) {...;}

    2)define object type something like :

    struct U8

    u8 value;
    std::string toString();

    or a template class that would allow me to write
    Type<u8> mytype;
    Type<u16> mytype2;
    std::sring string = mytype.tostring();

    Actually I am looking for intersting ways of doing this simple thing.
    Vincent RICHOMME, Jan 27, 2006
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  2. Vincent RICHOMME

    Mike Wahler Guest

    You only need do any of that if there are already no
    stream operators defined for those types (at least
    some of which I suspect are typedefs for native types)

    If they are, just use an ostringstream;

    int i(2);
    std::eek:stringsream oss;
    oss << i;
    std::string s(oss.str());
    // string now contains the sequence of characters:
    '4', '2'

    IF that 'wxString' type is from third party library,
    it probably already includes stream operators.
    BTW why are you using both 'std::string' and 'wxString'?
    Why not choose one or the other?
    I'm typically more interested in keeping my code simple (thus
    more readable/maintainable). 'Interesting' often becomes
    'unnecessarily complex'.

    Mike Wahler, Jan 27, 2006
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  3. Vincent RICHOMME

    Ian Collins Guest

    The biggest problem with this approach is that the standard streaming
    operators don't give you an output of char types that is consistent with
    other integer types, which are used in his example (assuming u8 is a
    typedef to unsigned char).

    A simple conversion template could be an answer, especially if the
    output is to be formatted in some way,for example

    template <typename T> std::string
    toString( T value )
    std::eek:stringstream ss;

    ss << value;

    return ss.str();

    template <> std::string
    toString( uint8_t value )
    unsigned n = value;

    return toString( n );

    While over the top for a simple case, would be handy if something other
    than the value was to be output.
    Ian Collins, Jan 27, 2006
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