c++ - C++ 中的 const 指针与 const 引用

Question

根据下面的程序，我可以理解，引用前面的const关键字的意思是Const 对const值的引用，对吗？

#include <iostream>
using namespace std;

struct s
{
    int x;
};

int main(void)
{
    s a = {10}, b = {30};

    // IN POINTERS ----------------
    const s* ptrToConstValue;
    ptrToConstValue= &a;
    //ptrToConstValue->x = 30; 
    ptrToConstValue = &b;

    s* const constPtrToNonConstVaue = &a;
    constPtrToNonConstVaue->x = 40;
    //constPtrToNonConstVaue = &b;

    const s* const constPtrToConstValue = &a;
    //constPtrToConstValue = &b;
    //constPtrToConstValue->x = 30;


    // IN REFERENCES -------------
    const s& seemsToBeConstRefToConstValue = a;
    //s = b;
    //s.x = 30;

    return 0;
}

Answer 1

所以困惑是这样的:

X x;

X* px       = &x; // pointer to x
X* const px  = &x; // *const pointer* to x

const X* px   = &x; // pointer to *const x*
X const* px   = &x; // identical

const X* const px = &x; // *const pointer* to *const x*

现在作为引用，“指针部分”始终是 const:

X& rx = x;       // ref to x

X const& rx = x; // ref to const x
const X& rx = x; // identical