Currency to double
CodeGuru Home VC++ / MFC / C++ .NET / C# Visual Basic VB Forums Developer.com
Results 1 to 5 of 5

Thread: Currency to double

  1. #1
    Join Date
    Jun 2004
    Posts
    1,329

    Currency to double

    I'm trying to convert a Currency value (Colecurrency data type ) to a double


    The only thing I have found is to first convert the Currency value to a Cstring, via:


    CString = COleCurrency::Format


    then using atof to convert the Cstring to a real number.


    It's a two step process, does anyone know if there is an easier way?

  2. #2
    Join Date
    May 2005
    Location
    United States
    Posts
    526

    Re: Currency to double

    Well if you really want to do it in a single line then you could try something like this (assuming a COleCurrency object called c):
    Code:
    double d = (double)((CURRENCY)c).int64 / 10000.0;
    COleCurrency provides the means to cast to the CURRENCY type, which is a 64-bit integer scaled by 10,000. (It's actually defined as a union, so the currency value can be interpreted as a single 64-bit integer if that's supported, or as a struct with two separate 32-bit integers if need be. Hence the .int64 part of my code. See this MSDN entry for details.) So from there, you can cast the integer to a double and divide through by 10,000.

    You should consider, though, whether this is a good idea. The reason CURRENCY is defined as it is is to avoid the inaccuracies that invariably turn up when working with floating-point numbers. (See this FAQ for lots of information.) So you should be careful when converting such a value to its floating-point equivalent; if you intend to use the floating point representations in any manner of calculations, then your program will be prone to the errors described in that FAQ.

  3. #3
    Join Date
    Jun 2004
    Posts
    1,329

    Re: Currency to double

    Thanks, this worked.


    Another quick question:


    I can't get the Currencey field to display two frational (cents ) values when the currency is a round amount, i.e, no cents.

    For example if I want to display '100.00', the field always displays '100'.

    I tried setting the currency to :

    m_Curr1 = COleCurrency(100, 00);


    But, it I can never get the .00 to show up. Can you help me?

  4. #4
    Join Date
    Jun 2005
    Posts
    241

    Re: Currency to double

    I assume that you could check if there are two decimal places and if there is not, you could just add a ".00" to then end of the displayed answer.

  5. #5
    VictorN's Avatar
    VictorN is offline Super Moderator Power Poster
    Join Date
    Jan 2003
    Location
    Wallisellen (ZH), Switzerland
    Posts
    17,471

    Re: Currency to double

    Quote Originally Posted by ADSOFT
    For example if I want to display '100.00', the field always displays '100'.
    .....
    But, it I can never get the .00 to show up. Can you help me?
    I already recommended you (in other thread) the simplest way to achieve it.
    If you nevertheless, want to use your COleCurrency member variable and DDX_Text exchange mechanism - find thix API in MS source code:
    Code:
    void AFXAPI DDX_Text( CDataExchange* pDX, int nIDC, COleCurrency& value );
    and overwrite it (write your own version) to display '100.00'...
    However, (and you will see it!) it will be the same as to use the the simplest way but a bit longer...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


Windows Mobile Development Center


Click Here to Expand Forum to Full Width

This is a CodeGuru survey question.


Featured


HTML5 Development Center