On May 7, 2005, at 8:31 PM, David Roundy wrote:
On Sat, May 07, 2005 at 08:20:15PM +0100, Thomas Davie wrote:
On May 7, 2005, at 8:07 PM, Marcin 'Qrczak' Kowalczyk wrote:
The size is taken into account when such array type is an element of another array, and by sizeof.
int (*p)[50]; /* p may legally point only to arrays of 50 ints each */ ++p; /* p is assumed to point into an array, and is moved by one element, i.e. by 50 ints */
I'm not sure what you're trying to prove by saying that... There is still no type information that says that the contents of p are an array of 50 elements... I can still attempt to access element 51 and get a runtime memory error. The type of p is still int**, not "pointer to array of 50 ints"
No, int (*p)[50] is a multidimensional array, one of the most useless concepts in C, and is equivalent to int p[50][] (or is it p[][50]... I always get my matrix subscripts messed up).
In a multi-dimensional array, all the dimensions but the first (or last?) are fixed in size. Unfortunately, these are fixed at compile time, so there's no way to write a function that can act upon multidimensional arrays of arbitrary size. So we get the joy of writing terms like m [i+n*j] to deal with matrices... :o It appears I have grossly underestimated how much C checks at compile time... I still feel all warm and cuddly in the everything checked world of Haskell though. And with that... I wonder, is this topic perhaps diverging from discussing how to get list sizes checked with Haskell's type checker and moving onto something relatively irrelevant.
Bob