Objective-C returns Variable-sized object may not be initialized

Question

come from a Java background to this Objective-c compiler error. Why can't I specify the length of the byte array?

NSUInteger length = modul.length;
Byte d[length] = {0};//compiler error: Variable-sized object may not be initialized

Answer 1

looks like I can just do memset(d, 0,5*sizeof(int)); to initialize it..