单项选择题
                                 有以下程序:
  void f(int *x, int *y)
  
  int t:
  t=*x;*x=*y;*y=t;
  
  void main()
  
  int a[8]=1,2,3,4,5,6,7,8,i,*p,*q;
  p=a;q=&a[7];
  while(p<q)
  f(p,q);p++;q--;
  for(i=0;i<8;i++)
  printf("%d,",a[i]);
  
  程序运行后输出的结果是(  )。
                                
A.8,2,3,4,5,6,7,1, 
B.5,6,7,8,1,2,3,4,
C.1,2,3,4,5,6,7,8, 
D.8,7,6,5,4,3,2,1,