std::for_each
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| Definido no cabeçalho <algorithm>
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| template< class InputIt, class UnaryFunction > UnaryFunction for_each( InputIt first, InputIt last, UnaryFunction f ); |
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Aplica-se a
f determinado objeto função do resultado de cada dereferencing iterador na [first, last) gama, em ordem. Se InputIt é mutável iterador, f pode modificar os elementos da gama através do iterador dereferenced. Se f retorna um resultado, o resultado é ignorado.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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Índice |
[editar] Parâmetros
| first, last | - | a gama de aplicar a função de
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 | - | o objeto de função unária a ser aplicada
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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[editar] Valor de retorno
f. (até C++11)
std::move(f). (desde C++11)
[editar] Complexidade
Exactamente
last - first aplicações de fOriginal:
Exactly
last - first applications of fThe text has been machine-translated via Google Translate.
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[editar] Possível implementação
template<class InputIt, class UnaryFunction> UnaryFunction for_each(InputIt first, InputIt last, UnaryFunction f) { for (; first != last; ++first) { f(*first); } return f; } |
[editar] Exemplo
O exemplo a seguir utiliza um função lambda para aumentar todos os elementos de um vector e, em seguida, calcula uma soma deles:
Original:
The following example uses a função lambda 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.
You can help to correct and verify the translation. Click here for instructions.
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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'; }
Saída:
before: 3 4 2 9 15 267 after: 4 5 3 10 16 268 sum: 306
[editar] Veja também
| aplica-se uma função de uma série de elementos 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. (modelo de função) | |
| faixa para loop | executa loop sobre (desde C++11) alcance
Original: executes loop over range (desde C++11) The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
