std::fill_n
From cppreference.com
Defined in header <algorithm>
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template< class OutputIt, class Size, class T > void fill_n( OutputIt first, Size count, const T& value ); |
(until C++11) | |
template< class OutputIt, class Size, class T > OutputIt fill_n( OutputIt first, Size count, const T& value ); |
(since C++11) | |
Assigns the given value
to the first count
elements in the range beginning at first
if count > 0
. Does nothing otherwise.
Contents |
[edit] Parameters
first | - | the beginning of the range of elements to modify |
count | - | number of elements to modify |
value | - | the value to be assigned |
Type requirements | ||
-OutputIt must meet the requirements of OutputIterator .
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[edit] Return value
(none) | (until C++11) |
Iterator one past the last element assigned if count > 0 , first otherwise.
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(since C++11) |
[edit] Complexity
Exactly count
assignments, for count > 0
.
[edit] Possible implementation
template<class OutputIt, class Size, class T> OutputIt fill_n(OutputIt first, Size count, const T& value) { for (Size i = 0; i < count; i++) { *first++ = value; } return first; } |
[edit] Example
The following code uses fill_n()
to assign -1 to the first half of a vector of integers:
Run this code
#include <algorithm> #include <vector> #include <iostream> #include <iterator> int main() { std::vector<int> v1{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}; std::fill_n(v1.begin(), 5, -1); std::copy(begin(v1), end(v1), std::ostream_iterator<int>(std::cout, " ")); std::cout << "\n"; }
Output:
-1 -1 -1 -1 -1 5 6 7 8 9
[edit] See also
assigns a range of elements a certain value (function template) | |
(parallelism TS) |
parallelized version of std::fill_n (function template) |