C#交换两个变量的值

            int a = 10;              int b = 20;              Console.WriteLine("a={0},b={1}", a, b);                //方法一 交换ab              a = a ^ b;              b = a ^ b;              a = a ^ b;                  Console.WriteLine("a={0},b={1}", a, b);                 //方法二              a = a + b;              b = a - b;              a = a - b;                Console.WriteLine("a={0},b={1}", a, b);