std::fill
Defined in header <algorithm> | ||
|---|---|---|
| (1) | ||
template< class ForwardIt, class T > void fill( ForwardIt first, ForwardIt last, const T& value ); | (until C++20) | |
template< class ForwardIt, class T > constexpr void fill( ForwardIt first, ForwardIt last, const T& value ); | (since C++20) | |
template< class ExecutionPolicy, class ForwardIt, class T > void fill( ExecutionPolicy&& policy, ForwardIt first, ForwardIt last, const T& value ); | (2) | (since C++17) |
1) Assigns the given
value to the elements in the range [first, last).
2) Same as (1), but executed according to
policy. This overload does not participate in overload resolution unless std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is trueParameters
| first, last | - | the range of elements to modify |
| value | - | the value to be assigned |
| policy | - | the execution policy to use. See execution policy for details. |
| Type requirements | ||
-ForwardIt must meet the requirements of LegacyForwardIterator. |
||
Return value
(none).
Complexity
Exactly last - first assignments.
Exceptions
The overload with a template parameter named ExecutionPolicy reports errors as follows:
- If execution of a function invoked as part of the algorithm throws an exception and
ExecutionPolicyis one of the standard policies,std::terminateis called. For any otherExecutionPolicy, the behavior is implementation-defined. - If the algorithm fails to allocate memory,
std::bad_allocis thrown.
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
See also
| copy-assigns the given value to N elements in a range (function template) |
|
|
(C++11) | copies a range of elements to a new location (function template) |
| assigns the results of successive function calls to every element in a range (function template) |
|
| applies a function to a range of elements (function template) |
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