Namespaces
Variants
Actions

std::fill

From cppreference.com
< cpp‎ | algorithm
 
C++
 
Algorithm library
Constrained algorithms and algorithms on ranges (C++20)
Constrained algorithms, e.g. ranges::copy, ranges::sort, ...
Execution policies (C++17)
Non-modifying sequence operations
Batch operations
(C++17)
Search operations
(C++11)                (C++11)(C++11)

Modifying sequence operations
Copy operations
(C++11)
(C++11)
(C++11)
Swap operations
Transformation operations
Generation operations
fill
Removing operations
Order-changing operations
(until C++17)(C++11)
(C++20)(C++20)
Sampling operations
(C++17)

Sorting and related operations
Partitioning operations
Sorting operations
Binary search operations
(on partitioned ranges)
Set operations (on sorted ranges)
Merge operations (on sorted ranges)
Heap operations
Minimum/maximum operations
(C++11)
(C++17)
Lexicographical comparison operations
(C++20)
Permutation operations
C library
Numeric operations
Operations on uninitialized memory
 
Defined in header <algorithm>
(1)
template< class ForwardIt, class T >
void fill( ForwardIt first, ForwardIt last, const T& value );
 (constexpr since C++20)
(until C++26)
template< class ForwardIt, class T = typename std::iterator_traits

                                         <ForwardIt>::value_type >
constexpr void fill( ForwardIt first, ForwardIt last,

                     const T& value );
 (since C++26)
(2)
template< class ExecutionPolicy, class ForwardIt, class T >

void fill( ExecutionPolicy&& policy,

           ForwardIt first, ForwardIt last, const T& value );
 (since C++17)
(until C++26)
template< class ExecutionPolicy,

          class ForwardIt, class T = typename std::iterator_traits
                                         <ForwardIt>::value_type >
void fill( ExecutionPolicy&& policy,

           ForwardIt first, ForwardIt last, const T& value );
 (since C++26)
1) Assigns the given value to all elements in the range [first, last).
2) Same as (1), but executed according to policy.
This overload participates in overload resolution only if all following conditions are satisfied:

std::is_execution_policy_v<std::decay_t<ExecutionPolicy>> is true.

(until C++20)

std::is_execution_policy_v<std::remove_cvref_t<ExecutionPolicy>> is true.

(since C++20)

If value is not writable to first, the program is ill-formed.

Contents

[edit] Parameters

first, last - the pair of iterators defining the range of elements to modify
value - the value to be assigned
policy - the execution policy to use
Type requirements
-
ForwardIt must meet the requirements of LegacyForwardIterator.

[edit] Complexity

Exactly std::distance(first, last) assignments.

[edit] 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.

[edit] Possible implementation

fill (1) 
template<class ForwardIt,
         class T = typename std::iterator_traits<ForwardIt>::value_type>
void fill(ForwardIt first, ForwardIt last, const T& value)
{
    for (; first != last; ++first)
        *first = value;
}

[edit] Notes

Feature-test macro Value Std Feature
__cpp_lib_algorithm_default_value_type