Is it undefined behavior to dereference a dangling pointer?

Question

I can\'t find where in the standard that it says this program is undefined:

#include 

int main() 
{
    int *p;
    {
        int n = 45;
           


        

Answer 1

So first of all according to 3.7.3 Automatic storage duration storage of your object is released:

Block-scope variables explicitly declared register or not explicitly declared static or extern have automatic storage duration. The storage for these entities lasts until the block in which they are created exits.

And from 3.8 Object lifetime

Before the lifetime of an object has started but after the storage which the object will occupy has been allocated or, after the lifetime of an object has ended and before the storage which the object occupied is reused or released, any pointer that refers to the storage location where the object will be or was located may be used but only in limited ways

so dereferencing pointer to variable which storage released leads to UB