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cpp/algorithm/min element: differenze tra le versioni

Da cppreference.com.
< cpp‎ | algorithm
m (una revisione importata: Translate from the English version)
m (Use {{lc}}. Update links. Various fixes.)
 
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{{cpp/title|min_element}}
 
{{cpp/title|min_element}}
 
{{cpp/algorithm/navbar}}
 
{{cpp/algorithm/navbar}}
{{ddcl list begin}}
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{{begin}}
{{ddcl list header | algorithm}}
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{{header | algorithm}}
{{ddcl list item | num=1 |
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{{| num=1 |
 
template< class ForwardIt >  
 
template< class ForwardIt >  
 
ForwardIt min_element( ForwardIt first, ForwardIt last );
 
ForwardIt min_element( ForwardIt first, ForwardIt last );
 
}}
 
}}
{{ddcl list item | num=2 |
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{{| num=2 |
 
template< class ForwardIt, class Compare >
 
template< class ForwardIt, class Compare >
 
ForwardIt min_element( ForwardIt first, ForwardIt last, Compare comp );
 
ForwardIt min_element( ForwardIt first, ForwardIt last, Compare comp );
 
}}
 
}}
{{ddcl list end}}
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{{end}}
  
 
{{tr|Trova il più piccolo elemento nel {{tt|[first, last)}} gamma. La prima versione utilizza {{c|operator<}} per confrontare i valori, la seconda versione utilizza la funzione di confronto dato {{tt|comp}}.|Finds the smallest element in the range {{tt|[first, last)}}. The first version uses {{c|operator<}} to compare the values, the second version uses the given comparison function {{tt|comp}}.}}
 
{{tr|Trova il più piccolo elemento nel {{tt|[first, last)}} gamma. La prima versione utilizza {{c|operator<}} per confrontare i valori, la seconda versione utilizza la funzione di confronto dato {{tt|comp}}.|Finds the smallest element in the range {{tt|[first, last)}}. The first version uses {{c|operator<}} to compare the values, the second version uses the given comparison function {{tt|comp}}.}}
  
 
===Parametri===
 
===Parametri===
{{param list begin}}
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{{begin}}
{{param list item | first, last |{{tr| iteratori forward che definiscono l'intervallo di esaminare| forward iterators defining the range to examine}}}}
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{{| first, last |{{tr| iteratori forward che definiscono l'intervallo di esaminare| forward iterators defining the range to examine}}}}
{{param list cmp | cmp | p1=ForwardIt | if {{tt|*a}} is ''less'' than {{tt|*b}}}}  
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{{cmp | cmp | p1=ForwardIt | if {{tt|*a}} is ''less'' than {{tt|*b}}}}  
{{param list hreq}}
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{{hreq}}
{{param list req concept | ForwardIt | ForwardIterator}}
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{{req concept | ForwardIt | ForwardIterator}}
{{param list end}}
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{{end}}
  
 
===Valore di ritorno===
 
===Valore di ritorno===
Riga 85: Riga 85:
  
 
===Vedi anche===
 
===Vedi anche===
{{dcl list begin}}
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{{begin}}
{{dcl list template | cpp/algorithm/dcl list max_element}}
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{{| cpp/algorithm/max_element}}
{{dcl list template | cpp/algorithm/dcl list minmax_element}}
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{{| cpp/algorithm/minmax_element}}
{{dcl list template | cpp/algorithm/dcl list min}}
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{{| cpp/algorithm/min}}
{{dcl list end}}
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{{end}}
  
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[[es:cpp/algorithm/min element]]
 
[[es:cpp/algorithm/min element]]
 
[[fr:cpp/algorithm/min element]]
 
[[fr:cpp/algorithm/min element]]
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[[pt:cpp/algorithm/min element]]
 
[[pt:cpp/algorithm/min element]]
 
[[ru:cpp/algorithm/min element]]
 
[[ru:cpp/algorithm/min element]]
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Versione attuale delle 12:22, 2 lug 2013

 
 
Algoritmo libreria
Funzioni
Original:
Functions
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Non modifica le operazioni di sequenza
Original:
Non-modifying sequence operations
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Modifica delle operazioni di sequenza
Original:
Modifying sequence operations
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Partizionamento operazioni
Original:
Partitioning operations
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Ordinamento delle operazioni (su intervalli ordinati)
Original:
Sorting operations (on sorted ranges)
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Binarie (le operazioni di ricerca sui campi ordinati)
Original:
Binary search operations (on sorted ranges)
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Impostare le operazioni (su intervalli ordinati)
Original:
Set operations (on sorted ranges)
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Heap operazioni
Original:
Heap operations
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Minimo / massimo le operazioni
Original:
Minimum/maximum operations
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max
max_element
min
min_element
minmax(C++11)
minmax_element(C++11)
Operazioni numeriche
Original:
Numeric operations
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Libreria C
Original:
C library
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Elemento definito nell'header <algorithm>
template< class ForwardIt >
ForwardIt min_element( ForwardIt first, ForwardIt last );
(1)
template< class ForwardIt, class Compare >
ForwardIt min_element( ForwardIt first, ForwardIt last, Compare comp );
(2)
Trova il più piccolo elemento nel [first, last) gamma. La prima versione utilizza operator< per confrontare i valori, la seconda versione utilizza la funzione di confronto dato comp.
Original:
Finds the smallest element in the range [first, last). The first version uses operator< to compare the values, the second version uses the given comparison function comp.
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Indice

[modifica] Parametri

first, last -
iteratori forward che definiscono l'intervallo di esaminare
Original:
forward iterators defining the range to examine
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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. ​

Type requirements
-
ForwardIt must meet the requirements of ForwardIterator.

[modifica] Valore di ritorno

Iterator al più piccolo elemento nel [first, last) gamma. Se diversi elementi della gamma sono equivalenti al più piccolo elemento, restituisce l'iteratore al primo elemento tale. Restituisce last se il campo è vuoto.
Original:
Iterator to the smallest element in the range [first, last). If several elements in the range are equivalent to the smallest element, returns the iterator to the first such element. Returns last if the range is empty.
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[modifica] Complessità

Esattamente max(N-1,0) confronti, N = std::distance(first, last) dove.
Original:
Exactly max(N-1,0) comparisons, where N = std::distance(first, last).
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[modifica] Possibile implementazione

First version
template<class ForwardIt>
ForwardIt min_element(ForwardIt first, ForwardIt last)
{
    if (first == last) return last;
 
    ForwardIt smallest = first;
    ++first;
    for (; first != last; ++first) {
        if (*first < *smallest) {
            smallest = first;
        }
    }
    return smallest;
}
Second version
template<class ForwardIt, class Compare>
ForwardIt min_element(ForwardIt first, ForwardIt last, 
                            Compare comp)
{
    if (first == last) return last;
 
    ForwardIt smallest = first;
    ++first;
    for (; first != last; ++first) {
        if (comp(*first, *smallest)) {
            smallest = first;
        }
    }
    return smallest;
}

[modifica] Esempio

#include <algorithm>
#include <iostream>
#include <vector>
 
int main()
{
    std::vector<int> v{3, 1, 4, 1, 5, 9};
 
    std::vector<int>::iterator result = std::min_element(v.begin(), v.end());
    std::cout << "min element at: " << std::distance(v.begin(), result);
}

Output:

min element at: 1

[modifica] Vedi anche

restituisce l'elemento più grande in un intervallo
Original:
returns the largest element in a range
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(funzione di modello) [modifica]
restituisce l'elemento più piccolo e il più grande in un intervallo
Original:
returns the smallest and the largest element in a range
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(funzione di modello) [modifica]
restituisce il minore dei due elementi
Original:
returns the smaller of two elements
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(funzione di modello) [modifica]