std::slice_array<T>::operator=
From cppreference.com
< cpp | numeric | valarray | slice array
void operator=(const T& value )const; | (1) | |
void operator=(conststd::valarray<T>& val_arr )const; | (2) | |
const slice_array& operator=(const slice_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.
Contents |
[edit]Parameters
| value | - | a value to assign to all of the referred elements |
| val_arr | - | std::valarray to assign |
| other_arr | - | std::slice_array to assign |
[edit]Return value
1,2) (none)
3)*this
[edit]Example
Run this code
#include <iostream>#include <valarray> void print(charconst* remark, std::valarray<int>const& v ={}){std::cout<< remark;if(v.size()!=0){std::cout<<':';for(int e : v)std::cout<<' '<< e;}std::cout<<'\n';} int main(){std::valarray<int> v1{1, 2, 3, 4, 5, 6, 7, 8};std::slice_array<int> s1 = v1[std::slice(1, 4, 2)]; print("v1", v1); print("s1", s1); print("\n(1) operator=( const T& )"); print("s1 = 42"); s1 =42;// (1) print("s1", s1); print("v1", v1); print("\n(2) operator=( const std::valarray<T>& )");std::valarray<int> v2{10, 11, 12, 13, 14, 15}; print("v2", v2); print("s1 = v2"); s1 = v2;// (2) print("s1", s1); print("v1", v1); print("\n(3) operator=( const slice_array& )"); v1 ={1, 2, 3, 4, 5, 6, 7, 8};std::slice_array<int> s2 = v1[std::slice(0, 4, 1)];std::slice_array<int> s3 = v2[std::slice(1, 4, 1)]; print("v1", v1); print("v2", v2); print("s2", s2); print("s3", s3); print("s2 = s3"); s2 = s3;// (3) Note: LHS and RHS must have same size. print("s2", s2); print("v1", v1);}
Output:
v1: 1 2 3 4 5 6 7 8 s1: 2 4 6 8 (1) operator=( const T& ) s1 = 42 s1: 42 42 42 42 v1: 1 42 3 42 5 42 7 42 (2) operator=( const std::valarray<T>& ) v2: 10 11 12 13 14 15 s1 = v2 s1: 10 11 12 13 v1: 1 10 3 11 5 12 7 13 (3) operator=( const slice_array& ) v1: 1 2 3 4 5 6 7 8 v2: 10 11 12 13 14 15 s2: 1 2 3 4 s3: 11 12 13 14 s2 = s3 s2: 11 12 13 14 v1: 11 12 13 14 5 6 7 8
[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 |
