std::fill_n
From cppreference.com
Defined in header <algorithm>
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template< class OutputIterator, class Size, class T > void fill_n( OutputIterator first, Size count, const T& value ); |
(until C++11) (since C++11) |
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Assigns the given value 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 |
[edit] Return value
(none) (until C++11)
Iterator one past the last element assigned if count>0, first otherwise. (since C++11)
[edit] Complexity
Exactly count assignments, for count>0.
[edit] Possible implementation
template<class OutputIterator, class Size, class T> OutputIterator fill_n(OutputIterator 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:
#include <algorithm> #include <vector> #include <iostream> int main() { std::vector<int> v1{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}; std::fill_n(v1.begin(), 5, -1); for (vector<int>::iterator it = v1.begin(); it != v1.end(); ++it) { std::cout << *it << " "; } 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) |