交换两个数的三种方法：

#include <stdio.h>
void Swap(int* left,int* right)
{
	int temp;
	temp = *left;
	*left = *right;
	*right = temp;
}
int main()
{
	int a = 10;
	int b = 20;
	//法一
	Swap(&a, &b);

	//法二，不同第三个变量实现交换
	a = a + b - a;
	b = (a + b - a) >> 1;

	//法三
	a = a^b;
	b = a^b;
	a = a^b;

	printf("a=%d ,b=%d \n", a, b);
	getchar();
	return 0;
}