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std::indirect_array<T>::operator=

void operator=( const T& value ) const;
 (1) 
void operator=( const std::valarray<T>& val_arr ) const;
 (2) 
const indirect_array& operator=( const indirect_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.

Parameters

value - a value to assign to all of the referred elements
val_arr - std::valarray to assign
other_arr - std::indirect_array to assign

Return value

1-2) (none)
3) *this

Example

#include <iomanip>
#include <iostream>
#include <valarray>
#include <numeric>
 
void print(int n, std::valarray<int> const& v)
{
    std::cout << n << ':';
    for (int e : v)
        std::cout << std::setw(3) << e;
    std::cout << '\n';
}
 
int main()
{
    std::valarray<int> v(8);
    std::iota(std::begin(v), std::end(v), 0);
    print(1, v);
 
    std::valarray<std::size_t> idx{1, 3, 5, 7};
    const std::indirect_array<int> ia = v[idx];
    // 'ia' refers to v[1], v[3], v[5], v[7]
    ia = -1; // (1), effectively:
             // v[1] = v[3] = v[5] = v[7] = -1;
    print(2, v);
 
    ia = /*std::valarray<int>*/{-1, -2, -3, -4}; // (2),
        // effectively: v[1]=-1, v[3]=-2, v[5]=-3, v[7]=-4;
    print(3, v);
 
    std::valarray<std::size_t> idx2{0, 2, 4, 6};
    const std::indirect_array<int> ia2 = v[idx2];
    // 'ia2' refers to v[0], v[2], v[4], v[6]
    ia = ia2; // (3), effectively:
              // v[1]=v[0], v[3]=v[2], v[5]=v[4], v[7]=v[6];
    print(4, v);
}

Output:

1:  0  1  2  3  4  5  6  7
2:  0 -1  2 -1  4 -1  6 -1
3:  0 -1  2 -2  4 -3  6 -4
4:  0  0  2  2  4  4  6  6

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

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