int a = 5; int b = 4; int temp = 0; temp = a; a = b; b = temp;
异或法：
int a = 5; int b = 6; a = a^b; b = a^b; a = a^b;
加减法：
int a = 5; int b = 56; a = a+b; b = a-b; a = a-b;
三种方法实现整型数值交换
原文：http://blog.51cto.com/13907933/2154275
