std::rotate – cppreference.com

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definiert in Header `<algorithm>`

`template< class ForwardIt > void rotate( ForwardIt first, ForwardIt n_first, ForwardIt last ); template< class ForwardIt > ForwardIt rotate( ForwardIt first, ForwardIt n_first, ForwardIt last );`		(bis C + +11) (seit C++11)

Tauscht die Elemente im Bereich [first, last) derart, dass das Element das erste Element n_first des neuen Bereichs gerät und n_first - 1 wird das letzte Element .

Original:

Swaps the elements in the range [first, last) in such a way, that the element n_first becomes the first element of the new range and n_first - 1 becomes the last element.

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Parameter

first, last	-	der Bereich der Elemente zu drehen Original: the range of elements to rotate The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
n_first	-	das Element, um zum Beginn des neuen Bereichs zu bewegen Original: the element to move to the beginning of the new range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
Type requirements
-`ForwardIt` must meet the requirements of `ValueSwappable` and `ForwardIterator`.
-The type of dereferenced `ForwardIt` must meet the requirements of `MoveAssignable` and `MoveConstructible`.

Rückgabewert

(None) (bis C + +11)

Original:

(none) (bis C + +11)

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Der Iterator gleich first + (last - n_first) (seit C++11)

Original:

The iterator equal to first + (last - n_first) (seit C++11)

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Komplexität

linear im Abstand first und last

Original:

linear in the distance between first and last

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Mögliche Implementierung

template<class ForwardIt>
void rotate(ForwardIt first, ForwardIt n_first, ForwardIt last)
{
    ForwardIt next = n_first;
    while (first != next) {
        std::swap(*first++, *next++);
        if (next == last) {
            next = n_first;
        } else if (first == n_first) {
            n_first = next;
        }
    }
}

Beispiel

std :: rotate ist eine gemeinsame Baustein in vielen Algorithmen. Dieses Beispiel zeigt, Insertion Sort in C + +

Original:

std::rotate is a common building block in many algorithms. This example demonstrates insertion sort in C++

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#include <vector>
#include <iostream>
#include <algorithm>
 
int main()
{
    std::vector<int> v{2, 4, 2, 0, 5, 10, 7, 3, 7, 1}; 
 
    std::cout << "before sort:      ";
    for(int n: v)
        std::cout << n << ' ';
    std::cout << '\n';

    // insertion sort
    for (auto i = v.begin(); i != v.end(); ++i) {
        std::rotate(std::upper_bound(v.begin(), i, *i), i, i+1);
    }
 
    std::cout << "after sort:       ";
    for(int n: v)
        std::cout << n << ' ';
    std::cout << '\n';

    // simple rotation to the left
    std::rotate(v.begin(), v.begin() + 1, v.end());

    std::cout << "simple rotate left  : ";
    for(int n: v)
        std::cout << n << ' ';
    std::cout << '\n';

    // simple rotation to the right
    std::rotate(v.rbegin(), v.rbegin() + 1, v.rend());

    std::cout << "simple rotate right : ";
    for(int n: v)
        std::cout << n << ' ';
    std::cout << '\n';
 
}

Output:

before sort:      2 4 2 0 5 10 7 3 7 1 
after sort:       0 1 2 2 3 4 5 7 7 10 
simple rotate left : 1 2 2 3 4 5 7 7 10 0
simple rotate right: 0 1 2 2 3 4 5 7 7 10

Siehe auch


	Kopien und drehen eine Reihe von Elementen Original: copies and rotate a range of elements The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (Funktions-Template) [edit]