不允许创建临时变量，交换两个数的内容

#include<stdio.h>

void exchang(int *x,int *y)
{
	*x = *x - *y;
	*y = *x + *y;
	*x = *y - *x;
    printf("%d %d\n",*x,*y);
}
int main()
{
	int a;
	int b;
         int *m=&a;
	int *n=&b;
	scanf("%d %d",&a,&b);
	exchang( m,n);
	return 0;
}