using System;

​

public class NumberSwapper

{

    public static void SwapNumbers(ref int a, ref int b)

    {

        // Input validation: Check for potential integer overflow.  While not strictly an *exception*, overflow is problematic.

        if ((a > 0 && b > int.MaxValue - a) || (a < 0 && b < int.MinValue - a))

        {

            throw new OverflowException("Potential integer overflow detected.");

        }

​

        // Optimized swapping using addition and subtraction (no extra memory).

        a = a + b;

        b = a - b;

        a = a - b;

    }

​

    public static void GetInputAndSwap()

    {

        try

        {

            Console.Write("Enter A: ");

            if (!int.TryParse(Console.ReadLine(), out int a))

            {

                Console.WriteLine("Invalid input for A. Please enter an integer.");

                return;

            }

​

            Console.Write("Enter B: ");

            if (!int.TryParse(Console.ReadLine(), out int b))

            {

                Console.WriteLine("Invalid input for B. Please enter an integer.");

                return;

            }

​

            SwapNumbers(ref a, ref b);

​

            Console.WriteLine("After Swapping");

            Console.WriteLine($"A: {a} and B: {b}");

        }

        catch (OverflowException ex)

        {

            Console.WriteLine($"Error: {ex.Message}");

        }

        catch (Exception ex)

        {

            Console.WriteLine($"An unexpected error occurred: {ex.Message}");

        }

    }

​

    public static void Main(string[] args)

    {

        GetInputAndSwap();

    }

}