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& sl_arr) const; |
(3) | (since C++11) |
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
sl_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 |
| sl_arr | - | std::indirect_array to assign |
Return value
1-2) (none)
3)
*this
Exceptions
May throw implementation-defined exceptions.
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
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