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std::prev

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C++
 
Biblioteca Iterator
Primitivas iterador
Original:
Iterator primitives
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Adaptadores de iterador
Original:
Iterator adaptors
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Iteradores fluxo
Original:
Stream iterators
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Operações iterador
Original:
Iterator operations
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prev
(C++11)
(C++11)
Variar de acesso
Original:
Range access
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(C++11)
(C++11)
 
Definido no cabeçalho <iterator>
template< class BidirIt >

BidirIt prev( BidirIt it,

              typename std::iterator_traits<BidirIt>::difference_type n = 1 );
 (desde C++11)
Retorne o antecessor nth de it iterador.
Original:
Return the nth predecessor of iterator it.
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Índice

[editar] Parâmetros

it -
um iterador
Original:
an iterator
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n -
número de it elementos devem ser descendentes
Original:
number of elements it should be descended
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Type requirements
-
BidirIt must meet the requirements of BidirectionalIterator.

[editar] Valor de retorno

O antecessor de nth it iterador.
Original:
The nth predecessor of iterator it.
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[editar] Possível implementação

template<class BidirIt>
BidirIt prev(BidirIt it, typename std::iterator_traits<BidirIt>::difference_type n = 1)
{
    std::advance(it, -n);
    return it;
}

[editar] Exemplo

#include <iostream>
#include <iterator>
#include <vector>
 
int main() 
{
    std::vector<int> v{ 3, 1, 4 };
 
    auto it = v.end();
 
    auto pv = std::prev(it, 2);
 
    std::cout << *pv << '\n';
}

Saída: 

1

[editar] Veja também

(C++11)
incrementar um iterador
Original:
increment an iterator
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(função) [edit]
avanços de um iterador por determinada distância
Original:
advances an iterator by given distance
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(função) [edit]
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