std::max - cppreference.com

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Elemento definito nell'header `<algorithm>`

`template< class T > const T& max( const T& a, const T& b );`	(1)

`template< class T, class Compare > const T& max( const T& a, const T& b, Compare comp );`	(2)

`template< class T > T max( std::initializer_list<T> ilist);`	(3)	(dal C++11)

`template< class T, class Compare > T max( std::initializer_list<T> ilist, Compare comp );`	(4)	(dal C++11)

1-2)

Restituisce il maggiore dei due valori.

Original:

Returns the greater of the two values.

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3-4)

Restituisce il massimo dei valori in ilist inizializzatore lista.

Original:

Returns the greatest of the values in initializer list ilist.

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I (1,3) versioni utilizzano operator< per confrontare i valori, i (2,4) versioni utilizzare la funzione di confronto dato comp.

Original:

The (1,3) versions use operator< to compare the values, the (2,4) versions use the given comparison function comp.

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Parametri

a, b	-	i valori da confrontare Original: the values to compare The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
ilist	-	inizializzatore lista con i valori da confrontare Original: initializer list with the values to compare The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.
comp	-	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 `T` can be implicitly converted to both of them.
Type requirements
-`T` must meet the requirements of `LessThanComparable`. for the overloads (1) and (3)
-`T` must meet the requirements of `CopyConstructible`. for the overloads (3) and (4)

Valore di ritorno

1-2)

La maggior a e b. Se sono equivalenti, ritorna a.

Original:

The greater of a and b. If they are equivalent, returns a.

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3-4)

Il più grande valore in ilist. Se i valori sono diversi equivalente al più grande, restituisce il più a sinistra.

Original:

The greatest value in ilist. If several values are equivalent to the greatest, returns the leftmost one.

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Complessità

1-2)

Constant

Original:

Constant

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3-4)

Lineare in ilist.size()

Original:

Linear in ilist.size()

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Possibile implementazione

First version
template<class T> const T& max(const T& a, const T& b) { return (a < b) ? b : a; }
Second version
template<class T, class Compare> const T& max(const T& a, const T& b, Compare comp) { return (comp(a, b)) ? b : a; }
Third version
template< class T > T max( std::initializer_list<T> ilist) { return *std::max_element(ilist.begin(), ilist.end()); }
Fourth version
template< class T, class Compare > T max( std::initializer_list<T> ilist, Compare comp ) { return *std::max_element(ilist.begin(), ilist.end(), comp); }

Esempio

#include <algorithm>
#include <iostream>
#include <string> 
int main()
{
    std::cout << "larger of 1 and 9999: " << std::max(1, 9999) << '\n'
              << "larger of 'a', and 'b': " << std::max('a', 'b') << '\n'
              << "longest of \"foo\", \"bar\", and \"hello\": " <<
                  std::max( { "foo", "bar", "hello" },
                            [](const std::string& s1, const std::string& s2) {
                                 return s1.size() < s2.size();
                             }) << '\n';
}

Output:

larger of 1 and 9999: 9999
larger of 'a', and 'b': b
longest of "foo", "bar", and "hello": hello

Vedi anche


min	restituisce il minore dei due elementi Original: returns the smaller 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. (funzione di modello) [modifica]

minmax (C++11)	restituisce l'. più grande e più piccolo dei due elementi Original: returns the larger and the smaller 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. (funzione di modello) [modifica]

max_element	restituisce l'elemento più grande in un intervallo Original: returns 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. (funzione di modello) [modifica]