Solved

date and time formats?

Posted on 1998-12-11
4
229 Views
Last Modified: 2008-03-06
hi,
I'm searching for date and time formats (international/computer/ANSI ....).
Anyone with a doc or web site?
 
0
Comment
Question by:nil_dib
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 22

Expert Comment

by:nietod
ID: 1179928
Not that I can help, but to clarify for other experts, do you mean storage formats (data formats) or do you mean "expression" formats.  i.e what people use to express times and dates?
0
 
LVL 4

Author Comment

by:nil_dib
ID: 1179929
Is there a difference between storage formats and "expression" formats?
The formats should be be used within my application ( e.g. timestamp ) but
should also displayed for the user ....
0
 
LVL 8

Accepted Solution

by:
Answers2000 earned 50 total points
ID: 1179930
It is up to you internally, there appear to be 3 common varieties of common ways to do this.

Internal formats :-

(a) seconds since start point (e.g. 1 Jan 1970).  With a 32bit integer number you get a range up to about 2038.  Examples <time.h> in C Standard library and CTime in MFC
(b) floating point since start point.  1 = 1 day.  Part days are stored as fractions.  Example COleTime in MFC.  COleTime has a range of about 100AD to 9999AD
(c) Store year, month, day as integers (use 4 digits for year !)

MFC and C libraries have routines to convert from (a) to (c).  MFC has a routine to convert from (b) to (c) too.

COleDateTime in MFC has a display mechanism (Format) and parsing mechanism (ParseDateTime)

In terms of display, I suggest you follow the user's locale settings.  The cultural norms in different countries vary widely, e.g.

D/M/Y - UK
M/D/Y - US
Y/M/D - I think Japan and Sweden
(and this isn't even getting to times)

There is an ISO standard for dates (8601), and a nice explanation at
http://www.cl.cam.ac.uk/~mgk25/iso-time.html

This basically suggests using Y/M/D.  Personally I don't think everybody should be forced to confirm with this (it's not a convienent to type in or read dates like this if you don't regularly use em)


0
 
LVL 22

Expert Comment

by:nietod
ID: 1179931
Huge difference.  A serial date is stored as a binary integer,where each day after a certain starting date is represented by a consevtive number.  i.e. 01/01/1900 might be 0 then 01/021900 might be 1 etc.  In a BCD you might store the date using 8 bytes that store the ASCII value of the date digits in year month day order, so 12/11/1998 would be stored as "19981211".  In packed BCD the values would be stored using HEX digits like 0x19,0x98,0x12,0x11.  There are dozens of other possibilities.  These have nothing to do with how the numbers are expressed to the user.
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Errors will happen. It is a fact of life for the programmer. How and when errors are detected have a great impact on quality and cost of a product. It is better to detect errors at compile time, when possible and practical. Errors that make their wa…
Often, when implementing a feature, you won't know how certain events should be handled at the point where they occur and you'd rather defer to the user of your function or class. For example, a XML parser will extract a tag from the source code, wh…
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The viewer will learn how to use the return statement in functions in C++. The video will also teach the user how to pass data to a function and have the function return data back for further processing.

691 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question