Question

What I want to do is something like this:

void dosth(bool& a) {
  a[2] = false;
}

int main() {
  bool a[10];

  dosth(a);

  return 0;
}

I want to call by reference, with an array as argument. How to realize this?

Thx

Answer 1

Like this:

typedef bool array_type[10];

void dosth(array_type& a)
{
    a[2] = false;
}

int main()
{
    array_type a;
    dosth(a);
}

Or without the typedef:

void dosth(bool (&a)[10])
{
    a[2] = false;
}

int main()
{
    bool a[10];
    dosth(a);
}

Or more generally:

template <size_t Size>
void dosth(bool (&a)[Size])
{
    /*static_*/assert(Size > 2);

    a[2] = false;
}

int main()
{
    bool a[10];
    dosth(a);
}

---

If you’re not in C++0x, you can implement a (simple) static_assert like this:

template <bool>
struct static_assert_type;

template <> // only true is defined
struct static_assert_type<true> {}

#define static_assert(x) { static_assert_type<(x)>(); }

Which allows you uncomment the static_assert and get a compile-time error if the array size is too small.