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std::accumulate

De cppreference.com
< cpp‎ | algorithm

 
 
Biblioteca de algoritmos
Políticas de ejecución (C++17)
Operaciones no modificadoras de secuencia
(C++11)(C++11)(C++11)
(C++17)
Operaciones modificadoras de secuencia
Operaciones en almacenamiento no inicializado
Operaciones de partición
Operaciones de ordenación
(C++11)
Operaciones de búsqueda binaria
Operaciones de set (en rangos ordenados)
Operaciones de pila
(C++11)
Operaciones minimo/maximo
(C++11)
(C++17)
Permutaciones
Operaciones numéricas
accumulate
(C++17)
Bibliotecas C
 
Definido en la cabecera <numeric>
template< class InputIt, class T >
T accumulate( InputIt first, InputIt last, T init );
(1)
template< class InputIt, class T, class BinaryOperation >

T accumulate( InputIt first, InputIt last, T init,

              BinaryOperation op );
(2)

Computes the sum of the given value init and the elements in the range [first, last). The first version uses operator+ to sum up the elements, the second version uses the given binary function op.

Contenido

[editar] Parámetros

first, last -
el intervalo de elementos de suma
Original:
the range of elements to sum
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.
init - initial value of the sum
op - binary operation function object that will be applied.

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 type Type1 must be such that an object of type T can be implicitly converted to Type1. The type Type2 must be such that an object of type InputIt can be dereferenced and then implicitly converted to Type2. The type Ret must be such that an object of type T can be assigned a value of type Ret. ​

Requerimientos de tipo
-
InputIt debe reunir los requerimientos de InputIterator.
-
T debe reunir los requerimientos de CopyAssignable y CopyConstructible.

[editar] Valor de retorno

The sum of the given value and elements in the given range.

[editar] Posible implementación

Primera versión
template<class InputIt, class T>
T accumulate(InputIt first, InputIt last, T value)
{
    for (; first != last; ++first) {
        value = value + *first;
    }
    return value;
}
Segunda versión
template<class InputIt, class T, class BinaryOperation>
T accumulate(InputIt first, InputIt last, T value, 
             BinaryOperation op)
{
    for (; first != last; ++first) {
        value = op(value, *first);
    }
    return value;
}

[editar] Ejemplo

#include <iostream>
#include <vector>
#include <numeric>
#include <string>
 
int multiply(int x, int y)
{
    return x*y;
}
 
std::string magic_function(std::string res, int x)
{
    return res += (x > 5) ? "b" : "s";
}
 
int main()
{
    std::vector<int> v{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
 
    int sum = std::accumulate(v.begin(), v.end(), 0);
    int product = std::accumulate(v.begin(), v.end(), 1, multiply);
    std::string magic = std::accumulate(v.begin(), v.end(), std::string(), 
                                        magic_function);
 
    std::cout << sum << '\n'
              << product << '\n'
              << magic << '\n';
}

Salida:

55
3628800
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[editar] Ver también

calcula las diferencias entre elementos adyacentes en un rango
Original:
computes the differences between adjacent elements in a range
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(plantilla de función) [editar]
calcula el producto interno de dos rangos de elementos
Original:
computes the inner product of two ranges of elements
The text has been machine-translated via Google Translate.
You can help to correct and verify the translation. Click here for instructions.

(plantilla de función) [editar]
calcula la suma parcial de una serie de elementos
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.

(plantilla de función) [editar]