ch2/2.32.cpp

[AlesaW]

// Method 1
const int null1 = 0;
int *p1 = null1;

// Method 5
constexpr int null2 = 0;
int *p5 = null2;

are invalid, leads to type conversion error.

[simonZ0919]

// pointer is supposed to store the address, here is a simple correction
int null = 0;
int *p = & null;

[superluminance]

@AlesaW 1 & 5 compile w/ visual studio compiler, but not in GCC.
@simonZ0919 Unfortunately your solution is not a correction.

[ColinM9991]

Tested this locally. 1 & 5 do not compile with MSVC.

As @simonZ0919 says, a pointer stores an address. The book itself gives the answer prior to this exercise section.

The following is correct.

int null = 0;
int *p = &null;

[lthiet]

Since this exercise was left in a section that talked about constexpr, I think the intention of the authors were to make use of constexpr to make this expression valid. I would not say that @simonZ0919 solution serves the purpose of learning about constexpr.