casting operator - const vs non-const

Question

I have this code sample:

class Number 
{ 
  int i;
  public:
    Number(int i1): i(i1) {}
    operator int() const {return i;}
};

What are

Answer 1

If you have a function like this:

void f(const Number& n)
{
  int n1 = n;
}

It will start giving compilation error if you remove const in the casting operator.