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std::max_element

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< 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
max_element
(C++11)
(C++17)
Permutaciones
Operaciones numéricas
Bibliotecas C
 
Definido en la cabecera <algorithm>
template< class ForwardIt >
ForwardIt max_element( ForwardIt first, ForwardIt last );
(1)
template< class ForwardIt, class Compare >
ForwardIt max_element( ForwardIt first, ForwardIt last, Compare comp );
(2)

Finds the greatest element in the range [first, last). The first version uses operator< to compare the values, the second version uses the given comparison function comp.

Contenido

[editar] Parámetros

first, last -
iteradores hacia adelante que definen el rango de examinar
Original:
forward iterators defining the range to examine
The text has been machine-translated via Google Translate.
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cmp - comparison function which returns ​true if if *a is less than *b.

The signature of the comparison function should be equivalent to the following:

 bool cmp(const Type1 &a, const Type2 &b);

The signature does not need to have const &, but the function must not modify the objects passed to it.
The types Type1 and Type2 must be such that an object of type ForwardIt can be dereferenced and then implicitly converted to both of them. ​

Requerimientos de tipo
-
ForwardIt debe reunir los requerimientos de ForwardIterator.

[editar] Valor de retorno

Iterator to the greatest element in the range [first, last). If several elements in the range are equivalent to the greatest element, returns the iterator to the first such element. Returns last if the range is empty.

[editar] Complejidad

Exactamente max(N-1,0) comparaciones, N = std::distance(first, last) donde .
Original:
Exactly max(N-1,0) comparisons, where N = std::distance(first, last).
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You can help to correct and verify the translation. Click here for instructions.

[editar] Posible implementación

Primera versión
template<class ForwardIt>
ForwardIt max_element(ForwardIt first, ForwardIt last)
{
    if (first == last) {
        return last;
    }
    ForwardIt largest = first;
    ++first;
    for (; first != last; ++first) {
        if (*largest < *first) {
            largest = first;
        }
    }
    return largest;
}
Segunda versión
template<class ForwardIt, class Compare>
ForwardIt max_element(ForwardIt first, ForwardIt last, 
                            Compare comp)
{
    if (first == last) {
        return last;
    }
    ForwardIt largest = first;
    ++first;
    for (; first != last; ++first) {
        if (comp(*largest, *first)) {
            largest = first;
        }
    }
    return largest;
}

[editar] Ejemplo

#include <algorithm>
#include <iostream>
#include <vector>
#include <cmath>
 
static bool abs_compare(int a, int b)
{
    return (std::abs(a) < std::abs(b));
}
 
int main()
{
    std::vector<int> v{ 3, 1, -14, 1, 5, 9 }; 
    std::vector<int>::iterator result;
 
    result = std::max_element(v.begin(), v.end());
    std::cout << "max element at: " << std::distance(v.begin(), result) << '\n';
 
    result = std::max_element(v.begin(), v.end(), abs_compare);
    std::cout << "max element (absolute) at: " << std::distance(v.begin(), result);
}

Salida:

max element at: 5
max element (absolute) at: 2

[editar] Ver también

devuelve el elemento más pequeño de un rango
Original:
returns the smallest element in a range
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You can help to correct and verify the translation. Click here for instructions.

(plantilla de función) [editar]
devuelve el elemento más pequeño y el más grande en un rango
Original:
returns the smallest and the largest element 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]
devuelve el mayor de los dos elementos
Original:
returns the larger of two 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]