程序代码：

#include<iostream>
using namespace std;

void fun(int &x, int y)
{ int t=x; x=y; y=t;}

int main( )
{ int a[2] = {23, 42};
  fun(a[1],a[0]);
  std::cout<<a[0]<<","<<a[1]<<std::endl;
  return 0;
}