单项选择题

下面程序的运行结果是
#include<iostream,h>
void fun(int*a,int*b)
int X= *a;
* a= *b; *b=X;
cout<< *a<< *b<<" ";
void main()
int x=1, y=2;
fun(&x,&y);
cout<<X<<y<<end1;

A.12 12
B.12 21
C.21 12
D.21 11