void Sawp(int *p1,int *p2)
{
    int tmp;
	tmp=*p1;
	*p1=*p2;
	*p2=tmp;
int main()
{
	int a=10;
	int b=20;
	Sawp(&a,&b);
	printf("%d %d\n",a,b);
	return 0;
}