TITLE: Allocating a 2D array with new


PROBLEM: jae@cstr.ed.ac.uk (John A. Elliott)

1) If you want to dynamically declare a multi-dim array, C++ should allow:

int *ia = new int [10][10];


RESPONSE: ark@alice.att.com (Andrew Koenig)
	  AT&T Bell Laboratories, Murray Hill NJ


Not quite.  If T is an array type, the type of `new T' is
`pointer to element of T.'  So, if you allocate an array of
arrays, what you get back should be a pointer to the initial
element of that array, which is itself an array.

You should therefore write

	int (*ia)[10] = new int [10][10];

Note that the first 10 after "new" can be an arbitrary expression
but the second one cannot -- it becomes part of the type of the result.