Result 0 in pointer?

Question

Code sample: https://code.sololearn.com/cxbA0y857Ozf

Please tell me why its showing up 0 there.

Answer 1

Its result is actually undefined behaviour, when it executes
x++;
++x;
the increment actually increment the value of x, which was the address of y. After that, *x is not the value of y anymore, but some undefined value