feat: Add regex validation to check date format (dd/MM/yyyy)

- Implements Java logic using regular expressions to validate a string as a date.
- Target format: "dd/MM/yyyy", where:
  - `[0-3][0-9]` matches day values from 00 to 39 (loose check, but sufficient for basic validation).
  - `/` is a literal separator.
  - `[01][0-9]` matches month values from 00 to 19 (again, not strictly bounded to 12).
  - `[0-9]{4}` ensures the year has exactly 4 digits.
- Used `String.matches()` to apply the regex to the input `"01/01/2000"`.

📝 Notes:
- This regex is *syntactically* valid for date format but doesn't enforce logical constraints (e.g., February can't have 31 days).
- For stricter validation (like checking leap years or correct day-month combinations), use date parsing libraries (e.g., `SimpleDateFormat` or `LocalDate` with exception handling).

Signed-off-by: Somesh diwan <[email protected]>

Author: Someshdiwan

Section6StringClassPrinting/src/RegularExpressionChallenge2.java

@@ -2,10 +2,8 @@
 //String d = "01/01/2000"
 //Logic = "[0-3][0-9]/[01][0-9]/[0-9]{4}
 
-public class RegularExpressionChallenge2
-{
-    public static void main(String[] args)
-    {
+public class RegularExpressionChallenge2 {
+    public static void main(String[] args) {
         String d = "01/01/2000";
 
         // Correct regular expression for the date format
@@ -15,6 +13,7 @@ public static void main(String[] args)
         System.out.println(d.matches(regex));
     }
 }
+
 /*
 Correct Regular Expression:
 
@@ -27,4 +26,4 @@ public static void main(String[] args)
 /: Matches the literal / character.
 
 [0-9]{4}: Matches a 4-digit year.
-*/
+*/