• Posts
  • RSS
  • ◂◂RSS
  • Contact

  • History of Zero-based Months?

    August 24th, 2022
    history, tech
    JavaScript is a language of many silly things, and one of them is:

    > new Date()
    Wed Aug 24 2022 ...
    > new Date().getFullYear()
    > new Date().getMonth()
    > new Date().getDate()

    It represents 2022-08-24 as (2022, 7, 24). One-based indexing for the year and day, but zero-based indexing for the month.

    In this case, however, the problem was copied from Java:

    getMonth: The value returned is between 0 and 11, with the value 0 representing January.

    getDate: The value returned is between 1 and 31 representing the day of the month.

    I'd love to blame Java, but they seem to have copied the problem from C:

    tm_mday: The day of the month, in the range 1 to 31.
    tm_mon:  The number of months since January, in the range 0 to 11.

    Looking at the Unix History repo, the first mention of "month (0-11)" is in 1973's Research Unix V4:

    The value is a pointer
    to an array whose components are
    .lp +5 5
    0      seconds
    .lp +5 5
    1      minutes
    .lp +5 5
    2      hours
    .lp +5 5
    3      day of the month (1-31)
    .lp +5 5
    4      month (0-11)
    .lp +5 5
    5      year \*- 1900
    .lp +5 5
    6      day of the week (Sunday = 0)
    .lp +5 5

    While this may have been an original decision by Dennis Ritchie, it's also possible it was copied from an even earlier system. Does anyone know?

    Comment via: facebook, hacker news

    Recent posts on blogs I like:

    Futurist prediction methods and accuracy

    I've been reading a lot of predictions from people who are looking to understand what problems humanity will face 10-50 years out (and sometimes longer) in order to work in areas that will be instrumental for the future and wondering how accurate thes…

    via Posts on September 12, 2022

    History of group sleeping

    Not as normal as it once was The post History of group sleeping appeared first on Otherwise.

    via Otherwise August 10, 2022

    On the Beach

    I really like going in the water and this beach is a great place for building sand castles and boogie boarding. I also like trying to float on top of big waves. I'm not very good at it. I only float on the flat waves.

    via Anna Wise's Blog Posts July 12, 2022

    more     (via openring)

  • Posts
  • RSS
  • ◂◂RSS
  • Contact