std::ignore
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<tbody> </tbody>| Definido no cabeçalho <tuple>
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const /*unspecified*/ ignore; |
(desde C++11) | |
Um objeto do tipo não especificado de tal forma que qualquer valor pode ser atribuído a ele sem nenhum efeito. Projetado para uso com std::tie quando descompactar um std::tuple, como um espaço reservado para os argumentos que não são usados .
Original:
An object of unspecified type such that any value can be assigned to it with no effect. Intended for use with std::tie when unpacking a std::tuple, as a placeholder for the arguments that are not used.
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Exemplo
desempacotar um par retornado por set.insert (), mas só guardar o booleano .
Original:
unpack a pair returned by set.insert(), but only save the boolean.
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 <iostream>
#include <string>
#include <set>
#include <tuple>
int main()
{
std::set<std::string> set_of_str;
bool inserted;
std::tie(std::ignore, inserted) = set_of_str.insert("Test");
if (inserted) {
std::cout << "Value was inserted sucessfully\n";
}
}
Saída:
Value was inserted sucessfully
cria um tuple de referências lvalue ou desempacota a tupla em objetos individuaisOriginal: creates a tuple of lvalue references or unpacks a tuple into individual objectsThe text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (modelo de função) | |