# 27 Algorithms library [algorithms]

## 27.7 Mutating sequence operations [alg.modifying.operations]

### 27.7.7 Generate [alg.generate]

```template<class ForwardIterator, class Generator> constexpr void generate(ForwardIterator first, ForwardIterator last, Generator gen); template<class ExecutionPolicy, class ForwardIterator, class Generator> void generate(ExecutionPolicy&& exec, ForwardIterator first, ForwardIterator last, Generator gen); template<class OutputIterator, class Size, class Generator> constexpr OutputIterator generate_n(OutputIterator first, Size n, Generator gen); template<class ExecutionPolicy, class ForwardIterator, class Size, class Generator> ForwardIterator generate_n(ExecutionPolicy&& exec, ForwardIterator first, Size n, Generator gen); template<input_or_output_iterator O, sentinel_for<O> S, copy_constructible F> requires invocable<F&> && indirectly_writable<O, invoke_result_t<F&>> constexpr O ranges::generate(O first, S last, F gen); template<class R, copy_constructible F> requires invocable<F&> && output_range<R, invoke_result_t<F&>> constexpr borrowed_iterator_t<R> ranges::generate(R&& r, F gen); template<input_or_output_iterator O, copy_constructible F> requires invocable<F&> && indirectly_writable<O, invoke_result_t<F&>> constexpr O ranges::generate_n(O first, iter_difference_t<O> n, F gen); ```
Let N be max(0, n) for the generate_n algorithms, and last - first for the generate algorithms.
Mandates: Size is convertible to an integral type ([conv.integral], [class.conv]).
Effects: Assigns the result of successive evaluations of gen() through each iterator in the range [first, first + N).
Returns: first + N.
Complexity: Exactly N evaluations of gen() and assignments.