std::is_partitioned – cppreference.com

Aus cppreference.com

definiert in Header `<algorithm>`

`template< class InputIt, class UnaryPredicate > bool is_partitioned( InputIt first, InputIt last, UnaryPredicate p );`		(seit C++11)

Versandkosten true wenn alle Elemente im Bereich [first, last) die das Prädikat erfüllen p vor allen Elementen, die nicht angezeigt werden. Gibt auch true wenn [first, last) ist leer .

Original:

Returns true if all elements in the range [first, last) that satisfy the predicate p appear before all elements that don't. Also returns true if [first, last) is empty.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Parameter

first, last	-	das Spektrum der Elemente zu überprüfen Original: the range of elements to check The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
p	-	unary predicate which returns `true` für die Elemente voraussichtlich in dem Anfang des Bereichs gefunden werden Original: for the elements expected to be found in the beginning of the range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. . The signature of the predicate function should be equivalent to the following: `bool pred(const Type &a);` The signature does not need to have `const &`, but the function must not modify the objects passed to it. The type `Type` must be such that an object of type `InputIt` can be dereferenced and then implicitly converted to `Type`.
Type requirements
-`InputIt` must meet the requirements of `InputIterator`.

Rückgabewert

true wenn der Bereich [first, last) leer ist oder von p partitioniert. false sonst .

Original:

true if the range [first, last) is empty or is partitioned by p. false otherwise.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Komplexität

An den meisten std::distance(first, last) Anwendungen p .

Original:

At most std::distance(first, last) applications of p.

The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

Mögliche Implementierung

template< class InputIt, class UnaryPredicate >
bool is_partitioned(InputIt first, InputIt last, UnaryPredicate p)
{
    for (; first != last; ++first)
        if (!p(*first))
            break;
    for (; first != last; ++first)
        if (p(*first))
            return false;
    return true;
}

Beispiel

#include <algorithm>
#include <array>
#include <iostream>

int main()
{
    std::array<int, 9> v = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    
    auto is_even = [](int i){ return i % 2 == 0; };
    std::cout.setf(std::ios_base::boolalpha);
    std::cout << std::is_partitioned(v.begin(), v.end(), is_even) << ' ';
    
    std::partition(v.begin(), v.end(), is_even);
    std::cout << std::is_partitioned(v.begin(), v.end(), is_even) << ' ';
    
    std::reverse(v.begin(), v.end());
    std::cout << std::is_partitioned(v.begin(), v.end(), is_even);
}

Output:

Siehe auch


	teilt einen Bereich von Elementen in zwei Gruppen Original: divides a range of elements into two groups 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]

	locates the partition point of a partitioned range (Funktions-Template) [edit]