std::fill

Defined in header <algorithm>

template< class ForwardIt, class T >
void fill( ForwardIt first, ForwardIt last, const T& value );

Assigns the given value to the elements in the range [first, last).

Parameters

first, last	-	the range of elements to modify
value	-	the value to be assigned
Type requirements
- `ForwardIt` must meet the requirements of `ForwardIterator`.

Return value

(none).

Complexity

Exactly last - first assignments.

Possible implementation

template< class ForwardIt, class T >
void fill(ForwardIt first, ForwardIt last, const T& value)
{
    for (; first != last; ++first) {
        *first = value;
    }
}

Example

The following code uses fill() to set all of the elements of a vector of integers to -1:

#include <algorithm>
#include <vector>
#include <iostream>
  
int main()
{
    std::vector<int> v{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
  
    std::fill(v.begin(), v.end(), -1);
  
    for (auto elem : v) {
        std::cout << elem << " ";
    }
    std::cout << "\n";
}

Output:

1	`-1 -1 -1 -1 -1 -1 -1 -1 -1 -1`

fill_n	assigns a value to a number of elements (function template)
copycopy_if (C++11)	copies a range of elements to a new location (function template)
generate	saves the result of a function in a range (function template)
transform	applies a function to a range of elements (function template)
std::experimental::parallel::fill (parallelism TS)	parallelized version of `std::fill` (function template)

Links:

http://en.cppreference.com/w/cpp/algorithm/fill

doc_CPP

2025-01-10 15:47:30

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