feat: Implement binary to decimal conversion using Scanner.useRadix(2)

- Prompt user to input a binary number (comprising only 0s and 1s).
- Configured Scanner to interpret input using base-2 (`useRadix(2)`).
- Used `nextInt()` to parse the binary string into a decimal integer.
- Wrapped parsing logic in a try-catch block to handle InputMismatchException.
  - Displays an appropriate error message if non-binary input is entered.
- Used a `finally` block to ensure Scanner resource is properly closed.
- Included a comment with an example to explain the binary-to-decimal calculation.

Example:
  Input: 1010
  Output: Decimal value: 10

This commit demonstrates robust input handling and introduces a simple yet effective use of Java's radix-based parsing for binary number systems.

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

Author: Someshdiwan

Section6StringClassPrinting/src/RegularExpressionChallenge.java

@@ -1,11 +1,7 @@
-//Find number binary or not.
-
-public class RegularExpressionChallenge
-{
-    public static void main(String[] args)
-    {
+public class RegularExpressionChallenge {
+    public static void main(String[] args) {
         int b = 1000110;
         String str = String.valueOf(b);
-        System.out.println(str.matches( "[01]*"));
+        System.out.println(str.matches("[01]*"));
     }
-}
+}