std::valarray<T>::cshift

 

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valarray::valarray valarray::~valarray valarray::operator= valarray::operator[] valarray::swap valarray::size valarray::resize valarray::sum valarray::min valarray::max valarray::shift valarray::cshift valarray::apply	valarray::operator+valarray::operator-valarray::operator~valarray::operator! valarray::operator+=valarray::operator-=valarray::operator*=valarray::operator/=valarray::operator%=valarray::operator&=valarray::operator|=valarray::operator^=valarray::operator<<=valarray::operator>>=
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valarray<T> cshift( int count ) const;

Returns a new valarray of the same size with elements whose positions are shifted circularly by count elements.

A non-negative value of count shifts the elements circularly left count places and a negative value of count shifts the elements circularly right -count places.

Parameters

count

-

number of positions to shift the elements by

Return value

The resulting valarray with circularly shifted elements.

Notes

The function can be implemented with the return type different from std::valarray. In this case, the replacement type has the following properties:

• All const member functions of std::valarray are provided.
• std::valarray, std::slice_array, std::gslice_array, std::mask_array and std::indirect_array can be constructed from the replacement type.
• For every function taking a const std::valarray<T>& except begin() and end()(since C++11), identical functions taking the replacement types shall be added;
• For every function taking two const std::valarray<T>& arguments, identical functions taking every combination of const std::valarray<T>& and replacement types shall be added.
• The return type does not add more than two levels of template nesting over the most deeply-nested argument type.

Example

Run this code

#include <iostream>
#include <valarray>
 
int main()
{
    std::valarray<int> v{1, 2, 3, 4, 5, 6, 7, 8};
 
    for (auto const& val : v)
        std::cout << val << ' ';
    std::cout << '\n';
 
    std::valarray<int> v2 = v.cshift(2);
 
    for (auto const& val : v2)
        std::cout << val << ' ';
    std::cout << '\n';
}

Output:

1 2 3 4 5 6 7 8 
3 4 5 6 7 8 1 2

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 618	C++98	the expression of the shifted elements contains zero-division if size() is ​0​	describes the new positions without using expressions

See also

shift

zero-filling shift the elements of the valarray (public member function)