std::adjacent_difference
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<tbody> </tbody>| Dclar dans l'en-tte <numeric>
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template< class InputIt, class OutputIt > OutputIt adjacent_difference( InputIt first, InputIt last, OutputIt d_first ); |
(1) | |
template< class InputIt, class OutputIt, class BinaryOperation > OutputIt adjacent_difference( InputIt first, InputIt last, OutputIt d_first, BinaryOperation op ); |
(2) | |
Calcule les diffrences entre la deuxime et la premire de chaque paire adjacente d'lments de la gamme
[first, last) et les crit dans la gamme de dbut d_first + 1. Copie non modifie de first est crit d_first. La premire version utilise operator- de calculer les diffrences, la deuxime version utilise la fonction binaire donn op .Original:
Computes the differences between the second and the first of each adjacent pair of elements of the range
[first, last) and writes them to the range beginning at d_first + 1. Unmodified copy of first is written to d_first. The first version uses operator- to calculate the differences, the second version uses the given binary function op.The text has been machine-translated via Google Translate.
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Opration quivalente:
Original:
Equivalent operation:
The text has been machine-translated via Google Translate.
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*(d_first) = *first;
*(d_first+1) = (*first+1) - *(first);
*(d_first+2) = (*first+2) - *(first+1);
*(d_first+3) = (*first+3) - *(first+2);
...
Paramtres
| first, last | - | la plage d'lments
Original: the 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. |
| d_first | - | le dbut de la plage de destination
Original: the beginning of the destination range The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
| op | - | binary operation function object that will be applied. The signature of the function should be equivalent to the following:
The signature does not need to have |
| Type requirements | ||
-InputIt must meet the requirements of InputIterator.
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-OutputIt must meet the requirements of OutputIterator.
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Retourne la valeur
Il l'lment aprs le dernier lment crit .
Original:
It to the element past the last element written.
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Complexit
Exactement
(last - first) - 1 applications de l'opration binaireOriginal:
Exactly
(last - first) - 1 applications of the binary operationThe text has been machine-translated via Google Translate.
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Mise en uvre possible
| First version |
|---|
template<class InputIt, class OutputIt>
OutputIt adjacent_difference(InputIt first, InputIt last,
OutputIt d_first)
{
if (first == last) return d_first;
typedef typename std::iterator_traits<InputIt>::value_type value_t;
value_t acc = *first;
*d_first = acc;
while (++first != last) {
value_t val = *first;
*++d_first = val - acc;
acc = std::move(val);
}
return ++d_first;
}
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| Second version |
template<class InputIt, class T, class BinaryOperation>
OutputIt adjacent_difference(InputIt first, InputIt last,
OutputIt d_first, BinaryOperation op)
{
if (first == last) return d_first;
typedef typename std::iterator_traits<InputIt>::value_type value_t;
value_t acc = *first;
*d_first = acc;
while (++first != last) {
value_t val = *first;
*++d_first = op(val, acc);
acc = std::move(val);
}
return ++d_first;
}
|
Exemple
Le code suivant convertit une squence de nombres pairs de rptitions du numro 2 et convertit une squence de celles d'une squence de nombres de Fibonacci .
Original:
The following code converts a sequence of even numbers to repetitions of the number 2 and converts a sequence of ones to a sequence of Fibonacci numbers.
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#include <numeric>
#include <vector>
#include <iostream>
#include <functional>
int main()
{
std::vector<int> v{2, 4, 6, 8, 10, 12, 14, 16, 18, 20};
std::adjacent_difference(v.begin(), v.end(), v.begin());
for(auto n: v) {
std::cout << n << ' ';
}
std::cout << '\n';
v = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
std::adjacent_difference(v.begin(), v.end()-1, v.begin()+1, std::plus<int>()
for(auto n: v) {
std::cout << n << ' ';
}
std::cout << '\n';
}
Rsultat :
2 2 2 2 2 2 2 2 2 2
1 1 2 3 5 8 13 21 34 55
Voir aussi
calcule la somme partielle d'une srie d'lments Original: computes the partial sum of 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. (fonction gnrique) | |
rsume un ensemble d'lments Original: sums up 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. (fonction gnrique) | |