std::for_each
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| definiert in Header <algorithm>
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| template< class InputIt, class UnaryFunction > UnaryFunction for_each( InputIt first, InputIt last, UnaryFunction f ); |
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Wendet die angegebene Funktion Objekt
f dem Ergebnis der Dereferenzierung jeden Iterator im Bereich [first, last), in Ordnung. Wenn InputIt eine veränderliche Iterator ist, kann f die Elemente des Bereichs durch die dereferenziert Iterator ändern. Wenn f ein Ergebnis zurückgibt, wird das Ergebnis ignoriert .Original:
Applies the given function object
f to the result of dereferencing every iterator in the range [first, last), in order. If InputIt is a mutable iterator, f may modify the elements of the range through the dereferenced iterator. If f returns a result, the result is ignored.The text has been machine-translated via Google Translate.
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Inhaltsverzeichnis |
[Bearbeiten] Parameter
| first, last | - | der Bereich um die Funktion zu verarbeiten
Original: the range to apply the function to The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| f | - | die einstellige Funktion Objekt angewendet werden
Original: the unary function object to be applied The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| Type requirements | ||
-InputIt must meet the requirements of InputIterator.
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-UnaryFunction must meet the requirements of MoveConstructible. Does not have to be CopyConstructible
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[Bearbeiten] Rückgabewert
f. (bis C + +11)
std::move(f). (seit C++11)
[Bearbeiten] Komplexität
Genau
last - first Anwendungen fOriginal:
Exactly
last - first applications of fThe text has been machine-translated via Google Translate.
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[Bearbeiten] Mögliche Implementierung
template<class InputIt, class UnaryFunction> UnaryFunction for_each(InputIt first, InputIt last, UnaryFunction f) { for (; first != last; ++first) { f(*first); } return f; } |
[Bearbeiten] Beispiel
Im folgenden Beispiel wird ein Lambda-Funktion um alle Elemente eines Vektors inkrementieren und berechnet dann eine Summe von ihnen:
Original:
The following example uses a Lambda-Funktion to increment all of the elements of a vector and then computes a sum of them:
The text has been machine-translated via Google Translate.
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#include <vector> #include <algorithm> #include <iostream> struct Sum { Sum() { sum = 0; } void operator()(int n) { sum += n; } int sum; }; int main() { std::vector<int> nums{3, 4, 2, 9, 15, 267}; std::cout << "before: "; for (auto n : nums) { std::cout << n << " "; } std::cout << '\n'; std::for_each(nums.begin(), nums.end(), [](int &n){ n++; }); Sum s = std::for_each(nums.begin(), nums.end(), Sum()); std::cout << "after: "; for (auto n : nums) { std::cout << n << " "; } std::cout << '\n'; std::cout << "sum: " << s.sum << '\n'; }
Output:
before: 3 4 2 9 15 267 after: 4 5 3 10 16 268 sum: 306
[Bearbeiten] Siehe auch
| gilt eine Funktion einer Reihe von Elementen Original: applies a function to 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) | |
| range-for-Schleife | führt eine Schleife über Spektrum (seit C++11)
Original: executes loop over range (seit C++11) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
