uninitialized_fill_n uninitialized_fill_n Categories: allocators, algorithms Component type: function Prototype template <class ForwardIterator, class Size, class T> ForwardIterator uninitialized_fill_n(ForwardIterator first, Size n, const T& x); Description In C++, the operator new allocates memory for an object and then creates an object at that location by calling a constructor. Occasionally, however, it is useful to separate those two operations. [1] If each iterator in the range [first, first + n) points to uninitialized memory, then uninitialized_fill_n creates copies of x in that range. That is, for each iterator i in the range [first, first + n), uninitialized_fill_n creates a copy of x in the location pointed to i by calling construct(&*i, x). Definition Defined in the standard header memory, and in the nonstandard backward-compatibility header algo.h. Requirements on types ForwardIterator is a model of Forward Iterator. ForwardIterator is mutable. Size is an integral type that is convertible to ForwardIterator's distance type. ForwardIterator's value type has a constructor that takes a single argument of type T. Preconditions n is nonnegative. [first, first + n) is a valid range. Each iterator in [first, first + n) points to a region of uninitialized memory that is large enough to store a value of ForwardIterator's value type. Complexity Linear. Exactly n constructor calls. Example class Int { public: Int(int x) : val(x) {} int get() { return val; } private: int val; }; int main() { const int N = 137; Int val(46); Int* A = (Int*) malloc(N * sizeof(Int)); uninitialized_fill_n(A, N, val); } Notes [1] In particular, this sort of low-level memory management is used in the implementation of some container classes. See also Allocators, construct, destroy, uninitialized_copy, uninitialized_fill, raw_storage_iterator Copyright © 1999 Silicon Graphics, Inc. All Rights Reserved. TrademarkInformation