feat: Add utility class to reverse an array in place with print support

🧠 Logic:
- `reverseArray()` performs in-place reversal using two pointers (`left`, `right`) and swaps elements until they meet.
- `printArray()` displays the array contents with a prefix message for clarity.
- Main method demonstrates functionality by reversing a sample array `{1, 2, 8, 4, 5}`.
- Includes input validation for null arrays.

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

Author: Someshdiwan

Section9ArrayAB/Array 2.0/src/ArrayReverser.java

@@ -0,0 +1,50 @@
+/**
+ * Utility class for array reversal operations.
+ */
+public class ArrayReverser {
+    private static final String PRINT_SEPARATOR = " ";
+
+    /**
+     * Reverses the elements of an array in place.
+     *
+     * @param arr the array to be reversed
+     * @throws IllegalArgumentException if the input array is null
+     */
+    public static void reverseArray(int[] arr) {
+        if (arr == null) {
+            throw new IllegalArgumentException("Input array cannot be null");
+        }
+
+        int left = 0;
+        int right = arr.length - 1;
+
+        while (left < right) {
+            int temp = arr[left];
+            arr[left] = arr[right];
+            arr[right] = temp;
+            left++;
+            right--;
+        }
+    }
+
+    /**
+     * Prints the array elements with a space separator.
+     *
+     * @param arr the array to print
+     * @param prefix the prefix message to print before the array
+     */
+    private static void printArray(int[] arr, String prefix) {
+        System.out.println(prefix);
+        for (int num : arr) {
+            System.out.print(num + PRINT_SEPARATOR);
+        }
+        System.out.println();
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {1, 2, 8, 4, 5};
+        printArray(arr, "Original Array:");
+        reverseArray(arr);
+        printArray(arr, "Reversed Array:");
+    }
+}