I'm a bit confused what happened in the following code:
const int e = 2;
int* w = ( int* ) &e; // (1) cast to remove const-ness
*w = 5; // (2)
cout << *w << endl; // (3) outputs 5
cout << e << endl; // (4) outputs 2
cout << "w = " << w << endl; // (5) w points to the address of e
cout << "&e = " << &e << endl;
In (1), w points to the address of e. In (2), that value was changed to 5. However, when the values of *w and e were displayed, their values are different. But if you print value of w pointer and &e, they have the same value/address.
How come e still contained 2, even if it was changed to 5? Were they stored in a separate location? Or a temporary? But how come the value pointed by w is still the address of e?
As I said in my comment, once you modified the const value you are in undefined behaviour land, so it doesn't make much sense to talk about what is happening. But what the hell..
cout << *w << endl; // (3) outputs 5
cout << e << endl; // (4) outputs 2
At a guess, *w
is being evaluated at runtime, but e
is being treated as a compile time constant