#include<stdio.h>void f(int *x,int *y){int t;t=*x;*x=*y;*y=t;}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]);}其中有一段while(p>q),p,q是指针,怎么比较大小的?