Function convert

Function convert_weekday

fd::convert_weekday — Convert a weekday number from one reference system to another.

// In header: <fd/date_time.h>


constexpr int 
convert_weekday(int weekday, int inputIsoFirstDow, int outputIsoFirstDow);

Parameters:

`weekday`	0-based weekday number.
`inputIsoFirstDow`	First day of week according to ISO 8601.
`outputIsoFirstDow`	First day of week according to ISO 8601.

Returns:

Converted weekday number modulo 7.