初学不懂,这个b为什么等于1呢?

short *p1 = 0, *p2 = 0;
int b = 0;
int *a[5] = { 0 };
for (int i = 0; i < 5; i++)
{
    a[i] = (int *)i;
}
p1 = (short *)a[1];
p2 = (short *)a[3];
b = (p2 - p1);
cout << "b = "<< b << endl;

道理很简单，因为short占2个字节，而a[3]-a[1]=2，所以是2/2=1