std::fill

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

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

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

Parameters

Return value

(none).

Complexity

Exactly std::distance(first, last) 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 ExecutionPolicy is one of the standard policies, std::terminate is called. For any other ExecutionPolicy, the behavior is implementation-defined.
• If the algorithm fails to allocate memory, std::bad_alloc is thrown.

Possible implementation

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

Example

#include <algorithm>
#include <iostream>
#include <vector>
 
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';
}

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Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also