如何不使用第三个变量来交换两个数的值

第三种方法！！！

using System;
using System.Diagnostics;

namespace ConsoleApp7
{
    class Program
    {
        static void Main(string[] args)
        {
            int a = 111, b = 222;
            Stopwatch s = new Stopwatch();

            s.Restart();
            for (int i = 0; i < 10000000; i++)
            {
                Swap1(ref a, ref b);
            }
            s.Stop();
            Console.WriteLine(s.Elapsed);
            Console.WriteLine(s.ElapsedMilliseconds);
            Console.WriteLine(s.ElapsedTicks);

            Console.WriteLine();

            s.Restart();
            for (int i = 0; i < 10000000; i++)
            {
                Swap2(ref a, ref b);
            }
            s.Stop();
            Console.WriteLine(s.Elapsed);
            Console.WriteLine(s.ElapsedMilliseconds);
            Console.WriteLine(s.ElapsedTicks);

            Console.WriteLine();

            s.Restart();
            for (int i = 0; i < 10000000; i++)
            {
                Swap3(ref a, ref b);
            }
            s.Stop();
            Console.WriteLine(s.Elapsed);
            Console.WriteLine(s.ElapsedMilliseconds);
            Console.WriteLine(s.ElapsedTicks);

            Console.ReadKey();
        }

        public static void Swap1(ref int a, ref int b)
        {
            int temp = a;
            a = b;
            b = temp;
        }

        public static void Swap2(ref int a, ref int b)
        {
            a = a + b;
            b = a - b;
            a = a - b;
        }

        public static void Swap3(ref int a, ref int b)
        {
            a = a ^ b;
            b = a ^ b;
            a = a ^ b;
        }
    }
}

VS2013

VS2019