std::mask_array<T>::operator=
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std::valarray
std::mask_array
Member functions
mask_array::operator=
void operator=( const T& value ) const;
(1)
void operator=( const std::valarray <T>& val_arr ) const;
(2)
const mask_array& operator=( const mask_array& other_arr ) const;
(3)
Assigns values to all referred elements.
1) Assigns value to all of the elements.
2) Assigns the elements of val_arr to the referred to elements of *this.
3) Assigns the selected elements from other_arr to the referred to elements of *this.
[edit] Parameters
value
-
a value to assign to all of the referred elements
val_arr
-
std::valarray to assign
other_arr
-
std::mask_array to assign
[edit] Return value
1,2) (none)
3) *this
[edit] Example
Run this code
#include <iomanip> #include <iostream> #include <valarray> void print(std::valarray <int> const& v) { for (int e : v) std::cout << std::setw (2) << e << ' '; std::cout << '\n'; } int main() { const auto init = {1, 2, 3, 4, 5, 6, 7, 8}; std::valarray <int> v; v = init; v[(v % 2) == 0] = 0; // (1) print(v); v = init; v[(v % 2) == 1] = std::valarray <int>{-1, -2, -3, -4}; // (2) print(v); v = init; v[(v % 2) == 0] = v[(v % 2) == 1]; // (3) print(v); }
Output:
1 0 3 0 5 0 7 0 -1 2 -2 4 -3 6 -4 8 1 1 3 3 5 5 7 7
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 123 | C++98 | overload (2) was non-const | made const |
| LWG 253 | C++98 | the copy assignment operator was private | made public |
| LWG 621 | C++98 | the copy assignment operator was non-const | made const |