C++ puzzle
You have a C++ class with all methods marked const, no operator= and one private field x initialized by the constructor and not market mutable. Can a value of x change after an object is created?
For example, for a class below:
class Puzzle {
public:
Puzzle(int x_arg) : x(x_arg) {}
int get_x() const {
return x;
}
void someMethod1(...) const {
...
}
SomeReturnValue someMethod2(...) const {
...
}
private:
// Disable default operator=
Puzzle& operator=(const Puzzle&);
int x;
};
Can x change and how?
The code must compile with no warnings. Rule out abuses like direct memory writes, incorrect casts or casting away constness like:
class Puzzle {
public:
...
void set_x(int new_x) const {
// This is abusive and doesn't count.
const_cast<Puzzle *>(this)->x = new_x;
}
...
};
See the solution.
