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8.4.5
ISO Year-Week-Day and Date |
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This section contains the SCDTL routines that interconvert the ISO_YWD and DATE_INFO structures. The ISO_YWD structure permits representation of dates using the ISO year-week-day format. |
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8.4.5.1
iso_date_to_ywd () |
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This routine (Listing 8.13) converts a date expressed as a DATE_INFO structure, in a year, month, and day format, to an ISO_YWD structure, expressing the same date in the form of a year, week, and day. The week is the ISO week number, and the day is the ISO day in the week. |
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8.4.5.2
iso_ywd_to_date () |
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This routine (Listing 8.14) converts a date expressed as an ISO_YWD structure, in a year, week, and day format, to a DATE_INFO structure, expressing the same date in the form of a year, month, and day. The week is the ISO week number, and the ISO_YWD day is the ISO day in the week. |
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| Listing 8.13 | |
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/*
Following code checks for December dates which are part of the
first week of the next year.
*/
if (m == 12)
{
if (ywd.week == 1)
ywd.year++;
}
jd = date_to_JD0 (date);
ywd.day = day_of_week_index_JD0 (jd);
if (ywd.day == 0)
ywd.day = 7;
return (ywd);
}
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