Date conversion Haskell program added (#5629)

Co-authored-by: Riyazul555 <riyazulislam2003@gmail.com>

program/program/convert-standard-date-format-to-julian-date-and-vice-versa/convert_standard_date_format_to_julian_date_and_vice-versa.hs

@@ -0,0 +1,21 @@
+import Data.Time.Calendar
+import Data.Time.Calendar.OrdinalDate
+
+-- Function to convert standard date format (year, month, day) to Julian date
+toJulianDate :: Integer -> Int -> Int -> Day
+toJulianDate year month day = fromGregorian year month day
+
+-- Function to convert Julian date to standard date format (year, month, day)
+fromJulianDate :: Day -> (Integer, Int, Int)
+fromJulianDate date = toGregorian date
+
+-- Example usage
+main :: IO ()
+main = do
+    -- Convert standard date format to Julian date
+    let julianDate = toJulianDate 2024 4 9
+    putStrLn $ "Julian date: " ++ show julianDate
+
+    -- Convert Julian date to standard date format
+    let (year, month, day) = fromJulianDate julianDate
+    putStrLn $ "Standard date format: " ++ show year ++ "-" ++ show month ++ "-" ++ show day