Const 指针

int a = 0, b = 2;

const int* pA = &a; // pointer-to-const. `a` can't be changed through this
int* const pB = &a; // const pointer. `a` can be changed, but this pointer can't.
const int* const pC = &a; // const pointer-to-const.

//Error: Cannot assign to a const reference
*pA = b;

pA = &b;

*pB = b;

//Error: Cannot assign to const pointer
pB = &b;

//Error: Cannot assign to a const reference
*pC = b;

//Error: Cannot assign to const pointer
pC = &b;