const its usage

const int * p1; in this case, the format p1 its space can be change.
int const * p2; in this case, the format p2 its pointer can not be change.
for example.
p1 =&i;
p2 =&j;
this case, p1=&l;also can equal to &k;
p2=&j;
p2 only equal to &j;
this pointer can not be changed.
void fun(const int i)
{
i++;(running wrong report)
}
void fun(const int *p)
{
(*p)++;(running wrong report)
}
const int i =0;
also equal to int const i =0;