Changing value of const int using using pointer [duplicate]

Answer 1

In the C Standard mofiying a constant is an undefined behaviour. It means that anything could happen it depends on the machine you're running and the compiler your using. In some cases constants are puted on read-only memory and modifying it's value will cause the program to crash.

Exemple of the error generated by the GCC compiler:

error: assignment of read-only location '* p'
  *p = 11;
     ^

Answer 2

Modifying a const variable (directly or through a pointer) invokes undefined behavior. You may not get the same result in another machine.