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fill_n

 Category: algorithms Component type: function

Prototype

```template <class OutputIterator, class Size, class T>
OutputIterator fill_n(OutputIterator first, Size n, const T& value);
```

Description

Fill_n assigns the value value to every element in the range [first, first+n). That is, for every iterator i in [first, first+n), it performs the assignment *i = value. The return value is first + n.

Definition

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

Requirements on types

• OutputIterator is a model of Output Iterator.
• Size is an integral type (either signed or unsigned).
• T is a model of Assignable.
• T is convertible to a type in OutputIterator's set of value types.

Preconditions

• n >= 0.
• There is enough space to hold n values. That is, [first, first+n) is a valid range.

Complexity

Linear. Fill_n performs exactly n assignments.

Example

```vector<double> V;
fill_n(back_inserter(V), 4, 42);
assert(V.size() == 4 && V[0] == 42 && V[1] == 42 && V[2] == 42 && V[3] == 42);
```