c++ - Deletion of reference underlying -

what happen reference if underlying variable whom referring got deleted?

for e.g. why below code giving 12 output checked both on gcc , msvc

int *x = new int(1); int& y = *x; delete x; x=null; int z = 12; y=z; cout<<"y = "<<y<<endl; 

accessing object memory has been deleted undefined behaviour, regardless of whether directly or through reference.

the fact code outputs 12 on gcc , msvc largely irrelevant: output 13, or 42, or potato , still standard-conformant.