三种方法实现整型数值交换

临时变量法：

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;