C++ quiz. Given the following code: <pre><code class="cpp">s

Given the following code:

struct A
{
    /*keyword*/ int field;
};

int main()
{
    A a;
    const A& b = a;
    b.field = 0;
    return 0;
}

What access specifier must be in place /*keyword*/ to make the code compile and run successfully?

mutable
const
public
private
virtual
static

Explanation

The keyword mutable before the data field allows you to modify the value of this field, even if it is in a constant object.
The keyword static does not fit, because in this case it is necessary to define A::field outside the class so that the linker knows the memory address at which the value of A::field is stored.