std::generate

 

C++

Language

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Utilities library

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Algorithms library

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Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

 

Algorithm library

Functions
Non-modifying sequence operations
all_of any_of none_of (C++11) (C++11) (C++11) for_each count count_if mismatch equal	find find_if find_if_not (C++11) find_end find_first_of adjacent_find search search_n
Modifying sequence operations
copy copy_if (C++11) copy_n (C++11) copy_backward move (C++11) move_backward (C++11) fill fill_n transform generate generate_n remove remove_if remove_copy remove_copy_if	replace replace_if replace_copy replace_copy_if swap swap_ranges iter_swap reverse reverse_copy rotate rotate_copy random_shuffle shuffle   (C++11) unique unique_copy
Partitioning operations
is_partitioned (C++11) partition partition_copy (C++11)	stable_partition partition_point (C++11)
Sorting operations (on sorted ranges)
is_sorted (C++11) is_sorted_until (C++11) sort	partial_sort partial_sort_copy stable_sort nth_element
Binary search operations (on sorted ranges)
lower_bound upper_bound	binary_search equal_range
Set operations (on sorted ranges)
merge inplace_merge includes	set_difference set_intersection set_symmetric_difference set_union
Heap operations
is_heap is_heap_until (C++11) make_heap	push_heap pop_heap sort_heap
Minimum/maximum operations
max max_element min min_element minmax (C++11) minmax_element (C++11)	lexicographical_compare is_permutation (C++11) next_permutation prev_permutation
Numeric operations
iota (C++11) accumulate inner_product	adjacent_difference partial_sum
C library
qsort	bsearch

 

Defined in header <algorithm>
template< class ForwardIt, class Generator > void generate( ForwardIt first, ForwardIt last, Generator g );

Assigns each element in range [first, last) a value generated by the given function object g.

Parameters

first, last	-	the range of elements to generate
g	-	generator function object that will be called. The signature of the function should be equivalent to the following: Ret fun(); The type  Ret must be such that an object of type ForwardIt can be dereferenced and assigned a value of type  Ret. ​
Type requirements
- ForwardIt must meet the requirements of ForwardIterator.

Return value

(none)

Complexity

Exactly std::distance(first, last) invocations of g() and assignments.

Possible implementation

template<class ForwardIt, class Generator> void generate(ForwardIt first, ForwardIt last, Generator g) { while (first != last) { *first++ = g(); } }

Example

The following code fills a vector with random numbers:

run this code

#include <algorithm>
#include <iostream>
#include <cstdlib>
 
int main()
{
    std::vector<int> v(5);
    std::generate(v.begin(), v.end(), std::rand); // Using the C function rand()
 
    std::cout << "v: ";
    for (auto iv: v) {
        std::cout << iv << " ";
    }
    std::cout << "\n";
}

Possible output:

v: 52894 15984720 41513563 41346135 51451456

See also

fill	assigns a range of elements a certain value (function template)
generate_n	saves the result of N applications of a function (function template)