Passing 2D array with variable dimensions as function argument

Question

I just saw the following code among the successful submissions at codechef.

http://www.codechef.com/viewplaintext/1595846

I used to think that

float max(int n,int arr[n][n])
{....}

is not allowed in C++ (as 'n' is a variable). My CodeBlocks (on windows) with MinGW [gcc 4.4] gives compile time error. that "error: array bound is not an integer constant.

Then how can be such a solution be accepted by CodeChef's judge. Is there any special flag that allows us to do that in C++???

EDIT: A link showing status as AC (accepted) : http://www.codechef.com/viewsolution/1595846

Answer 1

Variable-length automatic arrays are allowed in ISO C99, and as an extension GCC accepts them in C90 mode and in C++. These arrays are declared like any other automatic arrays, but with a length that is not a constant expression.

Ref: http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html