std::fill - cppreference.com (original) (raw)

| Defined in header | | | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | ------------------------------------- | | (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:

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

Contents

• 1 Parameters
• 2 Complexity
• 3 Exceptions
• 4 Possible implementation
• 5 Notes
• 6 Example
• 7 Defect reports
• 8 See also

[edit] Parameters

[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

[edit] Notes

[edit] Example

#include #include #include #include   void println(const auto& seq) { for (const auto& e : seq) std::cout << e << ' '; std::cout << '\n'; }   int main() { std::vector v{0, 1, 2, 3, 4, 5, 6, 7, 8}; println(v);   // set all of the elements to 8 std::fill(v.begin(), v.end(), 8); println(v);   std::vector<std::complex> nums{{1, 3}, {2, 2}, {4, 8}}; println(nums); #ifdef __cpp_lib_algorithm_default_value_type std::fill(nums.begin(), nums.end(), {4, 2}); #else std::fill(nums.begin(), nums.end(), std::complex{4, 2}); #endif println(nums); }

Output:

0 1 2 3 4 5 6 7 8 8 8 8 8 8 8 8 8 8 (1,3) (2,2) (4,8) (4,2) (4,2) (4,2)

[edit] Defect reports

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

[edit] See also

| | copy-assigns the given value to N elements in a range (function template) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | copies a range of elements to a new location (function template) [edit] | | | assigns the results of successive function calls to every element in a range (function template) [edit] | | | applies a function to a range of elements, storing results in a destination range (function template) [edit] | | | assigns a range of elements a certain value(algorithm function object)[edit] |