How to initialize member-struct in initializer list of C++ class?

Question

I have the following class definitions in c++:

struct Foo {
  int x;
  char array[24];
  short* y;
};

class Bar {
  Bar();

  int x;
  Foo foo;
};
         


        

Answer 1

In standard C++ you need to make a ctor for Foo.

struct Foo {

  Foo(int const a, std::initializer_list const b, short* c)
    : x(a), y(c) {
    assert(b.size() >= 24, "err");
    std::copy(b.begin(), b.begin() + 24, array);
  }

  ~Foo() { delete y; }

  int x;
  char array[24];
  short* y;
};

class Bar {

  Bar() : x(5), foo(5, {'a', 'b', ..., 'y', 'z'},
    new short(5)) { }

  private:

  int x;
  Foo foo;
};

In C++0x you may use uniform initialization list, but still you need dtor for Foo:

class Bar {

  Bar() : x(5), foo{5, new char[24]{'a', 'b', ..., 'y', 'z'},
    new short(5)} { }
  ~Bar() { delete[] foo.array; delete foo.y;}
  }
  private:

  int x;
  Foo foo;
};

To default initialize foo (as Bar() : foo(), x(8) { }) you need to give Foo a default ctor.