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fill


Category: algorithms	Component type: function

Prototype

template <class ForwardIterator, class T>
void fill(ForwardIterator first, ForwardIterator last, const T& value);

Description

Fill assigns the value value to every element in the range [first, last). That is, for every iterator i in [first, last), it performs the assignment *i = value.

Definition

Defined in the standard header algorithm, and in the nonstandard backward-compatibility header algo.h.

Requirements on types

ForwardIterator is a model of Forward Iterator. [1]
ForwardIterator is mutable.
T is a model of Assignable.
T is convertible to Forward Iterator's value type.

Preconditions

[first, last) is a valid range.

Complexity

Linear. Fill performs exactly last - first assignments.

Example

vector<double> V(4);
fill(V.begin(), V.end(), 137);
assert(V[0] == 137 && V[1] == 137 && V[2] == 137 && V[3] == 137);

Notes

[1] The reason that fill requires its argument to be a mutable forward iterator, rather than merely an output iterator, is that it uses a range [first, last) of iterators. There is no sensible way to describe a range of output iterators, because it is impossible to compare two output iterators for equality. The fill_n algorithm does have an interface that permits use of an output iterator.