不用第三个变量,调换两个变量的值

法①:算术运算
static void Main(string[] args)        {                       int a = 5;            int b = 6;            a = b - a;            b = b - a;            a = b + a;            Console.WriteLine("a:{0},b:{1}",a,b);            Console.Read();                }
法②:位运算
 static void Main(string[] args)        {            int a = 10, b = 12;             a = a ^ b;              b = a ^ b;             a = a ^ b;             Console.WriteLine("a:{0},b:{1}",a,b);            Console.Read();                }