NAME¶

std::valarray::cshift - std::valarray::cshift

Synopsis¶

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

See also¶

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

Hidden category:¶

* Pages with unreviewed LWG DR marker