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C Library Functions  - j2d (3)

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NAME

j2d(3f) - [M_time:JULIAN] given a JD (Julian Date) returns a date-time array DAT. (LICENSE:MIT)

CONTENTS

Synopsis
Description
Options
Returns
Example
Author
License

SYNOPSIS

function j2d(julian) result(dat)

    real(kind=realtime),intent(in),optional :: julian
    integer                                 :: dat(8)

DESCRIPTION

Converts a Julian Date to a DAT date-time array.

OPTIONS

julian	A Julian Date (JD) is the number of days since noon (not midnight) on January 1st, 4713 BC. If not present, use current time.

RETURNS

dat	Integer array holding a "DAT" array, similar in structure to the array returned by the intrinsic DATE_AND_TIME(3f):

                dat=[ year,month,day,timezone,hour,&
                 & minutes,seconds,milliseconds]

EXAMPLE

Sample program:

    program demo_j2d
    use M_time, only : j2d, d2j, fmtdate, realtime
    implicit none
    integer,parameter   :: dp=kind(0.0d0)
    real(kind=realtime) :: today
    integer             :: dat(8)
       call date_and_time(values=dat) ! get the date using intrinsic
       today=d2j(dat)                  ! convert today to Julian Date
       write(*,*)’Today=’,fmtdate(j2d(today))
       ! math is easy with Julian Days and Julian Dates
       write(*,*)’Yesterday=’,fmtdate(j2d(today-1.0_dp))
       write(*,*)’Tomorrow=’,fmtdate(j2d(today+1.0_dp))
    end program demo_j2d

results:

    Today=Tuesday, July 19th, 2016 08:48:20 AM
    Yesterday=Monday, July 18th, 2016 08:48:20 AM
    Tomorrow=Wednesday, July 20th, 2016 08:48:20 AM

AUTHOR

John S. Urban, 2015

LICENSE

    MIT

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Nemo Release 3.1

j2d (3)

June 29, 2025

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