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    <metanoindex/>

     
    C++
     
    Bibliothque d'algorithmes
    Fonctions
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    Functions
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    Non-modification de la squence des oprations
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    Non-modifying sequence operations
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    Modification de la squence des oprations
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    Modifying sequence operations
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    Partitioning operations
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    Oprations de tri (sur les gammes tris)
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    Sorting operations (on sorted ranges)
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    is_sorted (C++11)
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    Oprations binaires de recherche (sur les gammes tris)
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    Binary search operations (on sorted ranges)
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    Dfinir les oprations (sur les gammes tris)
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    Set operations (on sorted ranges)
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    Heap operations
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    <tbody> </tbody>
    Dclar dans l'en-tte <numeric>
    template< class InputIt1, class InputIt2, class T > T inner_product( InputIt1 first1, InputIt1 last1, InputIt2 first2, T value );
    		 (1)
    template< class InputIt1, class InputIt2, class T, class BinaryOperation1, class BinaryOperation2 > T inner_product( InputIt1 first1, InputIt1 last1, InputIt2 first2, T value, BinaryOperation1 op1, BinaryOperation2 op2 );
    		 (2)
    Calcule produit scalaire (soit la somme des produits) de l'[first1, last1) gamme et un autre dbut de la plage first2. La premire version utilise pour calculer operator* produit des paires d'lments et operator+ de rsumer les produits, la deuxime version utilise op2 et op1 pour ces tches respectivement .
    Original:
    Computes inner product (i.e. sum of products) of the range [first1, last1) and another range beginning at first2. The first version uses operator* to compute product of the element pairs and operator+ to sum up the products, the second version uses op2 and op1 for these tasks respectively.
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    Paramtres

    first1, last1 -
    la premire gamme d'lments
    Original:
    the first range of elements
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    first2 -
    le dbut de la seconde gamme d'lments
    Original:
    the beginning of the second range of elements
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    value -
    valeur initiale de la somme des produits
    Original:
    initial value of the sum of the products
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    op1 - binary operation function object that will be applied.
    Cette fonction prend une valeur renvoye par op2 et la valeur de courant de l'accumulateur et produit une nouvelle valeur stocker dans l'accumulateur .
    Original:
    This function takes a value returned by op2 and the current value of the accumulator and produces a new value to be stored in the accumulator.
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    The signature of the function should be equivalent to the following:

    Ret fun(const Type1 &a, const Type2 &b);

    The signature does not need to have const &.
    The types Type1 and Type2 must be such that objects of types T and Type3 can be implicitly converted to Type1 and Type2 respectively. The type Ret must be such that an object of type T can be assigned a value of type Ret.

    op2 - binary operation function object that will be applied.
    Cette fonction prend une valeur de chaque gamme et produit une nouvelle valeur .
    Original:
    This function takes one value from each range and produces a new value.
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    The signature of the function should be equivalent to the following:

    Ret fun(const Type1 &a, const Type2 &b);

    The signature does not need to have const &.
    The types Type1 and Type2 must be such that objects of types InputIt1 and InputIt2 can be dereferenced and then implicitly converted to Type1 and Type2 respectively. The type Ret must be such that an object of type Type3 can be assigned a value of type Ret.

    Type requirements
    -
    InputIt1, InputIt2 must meet the requirements of InputIterator.
    -
    T must meet the requirements of CopyAssignable and CopyConstructible.

    Retourne la valeur

    Le produit scalaire de deux gammes .
    Original:
    The inner product of two ranges.
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    Mise en uvre possible

    First version 
    template<class InputIt1, class InputIt2, class T>
T inner_product(InputIt1 first1, InputIt1 last1,
                InputIt2 first2, T value)
{
    while (first1 != last1) {
         value = value + *first1 * *first2;
         ++first1;
         ++first2;
    }
    return value;
}
    Second version 
    template<class InputIt1, class InputIt2,
         class T,
         class BinaryOperation1, class BinaryOperation2>
T inner_product(InputIt1 first1, InputIt1 last1,
                InputIt2 first2, T value,
                BinaryOperation1 op1
                BinaryOperation2 op2)
{
    while (first1 != last1) {
         value = op1(value, op2(*first1, *first2));
         ++first1;
         ++first2;
    }
    return value;
}

    Exemple

    #include <numeric>
#include <iostream>
#include <vector>
#include <functional>
int main()
{
    std::vector<int> a{0, 1, 2, 3, 4};
    std::vector<int> b{5, 4, 2, 3, 1};

    int r1 = std::inner_product(a.begin(), a.end(), b.begin(), 0);
    std::cout << "Inner product of a and b: " << r1 << '\n';

    int r2 = std::inner_product(a.begin(), a.end(), b.begin(), 0,
                                std::plus<int>(), std::equal_to<int>());
    std::cout << "Number of pairwise matches between a and b: " <<  r2 << '\n';
}

    Rsultat : 

    Inner product of a and b: 21
Number of pairwise matches between a and b: 2

    Voir aussi
    rsume un ensemble d'lments
    Original:
    sums up a range of elements
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    (fonction gnrique) [edit]
    calcule la somme partielle d'une srie d'lments
    Original:
    computes the partial sum of a range of elements
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    (fonction gnrique) [edit]
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