# nullptr address?

* NO nullptr address, it is Rvalue, such like 5,
  * int a = 5; // 5 has no address
* nullptr address
* [https://stackoverflow.com/questions/14189709/why-cant-you-take-the-address-of-nullptr](https://stackoverflow.com/questions/14189709/why-cant-you-take-the-address-of-nullptr)
