std::prev – cppreference.com

std::prev

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C++
 
Iterator Bibliothek
Iterator Primitiven
Original:
Iterator primitives
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iterator_traits
input_iterator_tag
output_iterator_tag
forward_iterator_tag
bidirectional_iterator_tag
random_access_iterator_tag
iterator
Iterator Adaptern
Original:
Iterator adaptors
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reverse_iterator
Stream-Iteratoren
Original:
Stream iterators
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istream_iterator
ostream_iterator
istreambuf_iterator
ostreambuf_iterator
Iterator Operationen
Original:
Iterator operations
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advance
distance
prev(C++11)
next(C++11)
Reichen Zugang
Original:
Range access
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begin(C++11)
end(C++11)
 
<tbody> </tbody>
definiert in Header <iterator>
template< class BidirIt > BidirIt prev( BidirIt it, typename std::iterator_traits<BidirIt>::difference_type n = 1 );
 (seit C++11)
Bringen Sie den nth Vorgänger Iterator it .
Original:
Return the nth predecessor of iterator it.
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Parameter

it -
ein Iterator
Original:
an iterator
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n -
Anzahl der Elemente it sollte abstammen
Original:
number of elements it should be descended
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Type requirements
-
BidirIt must meet the requirements of BidirectionalIterator.

Rückgabewert

Die nth Vorgänger Iterator it .
Original:
The nth predecessor of iterator it.
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Mögliche Implementierung

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

Beispiel

#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';
}

Output: 

1

Siehe auch