TITLE: intializing member data arrays


PROBLEM: drcc@lepomis.psych.upenn.edu (Andrew Olson)

Is it possible to initialize an array of objects using the constructor
initializer list?  To make this more concrete, consider the example ...


RESPONSE: clamage@Eng.Sun.COM (Steve Clamage), 23 Oct 95

Not with built-in arrays. Here's a simpler example:

	class T {
		U data[10];
	public:
		T();
	};

There is no way to initialize any of the members of T::data array with
a constructor initialization list. You can assign to the array elements
inside the constructor body. So U must be a type which does not require
explicit constructor parameters.

If you use an Array class, you can put an Array constructor in the
T constructor initialization list:

	class Array {
		U* d;
	public:
		Array(int size);
		Array(int size, int initval); // initialize all elements with initval
	};

	class T {
		Array data;
	public:
		T() : data(10) { ... }
		T(int init) : data(10, init) { ... }
	};

Realistically, you would probably use templates here, but I wanted to keep
the example as simple as possible.