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std::map::find

De cppreference.com
< cpp‎ | container‎ | map

 
 
 
std::map
Les fonctions membres
Original:
Member functions
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map::map
map::~map
map::operator=
map::get_allocator
Elément d'accès
Original:
Element access
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map::at
map::operator[]
Les itérateurs
Original:
Iterators
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map::begin
map::cbegin

(C++11)
map::end
map::cend

(C++11)
map::rbegin
map::crbegin

(C++11)
map::rend
map::crend

(C++11)
Capacité
Original:
Capacity
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map::empty
map::size
map::max_size
Modificateurs
Original:
Modifiers
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map::clear
map::insert
map::emplace (C++11)
map::emplace_hint (C++11)
map::erase
map::swap
Lookup
Original:
Lookup
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map::count
map::find
map::equal_range
map::lower_bound
map::upper_bound
Des observateurs
Original:
Observers
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map::key_comp
map::value_comp
 
iterator find( const Key& key );
const_iterator find( const Key& key ) const;
Recherche un élément avec la clé key.
Original:
Finds an element with key key.
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Sommaire

[modifier] Paramètres

key -
la valeur de clé de l'élément à rechercher
Original:
key value of the element to search for
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[modifier] Retourne la valeur

Itérateur pour un élément de key clé. Si aucun élément correspondant n'est trouvé, past-the-end (voir end()) itérateur est renvoyé .
Original:
Iterator to an element with key key. If no such element is found, past-the-end (see end()) iterator is returned.
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[modifier] Complexité

Logarithmic in the size of the container.

[modifier] Voir aussi

retourne le nombre d'éléments correspondant à la touche spécifique
Original:
returns the number of elements matching specific key
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(fonction membre publique) [edit]
rendements varient d'éléments correspondant à une clé spécifique
Original:
returns range of elements matching a specific key
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(fonction membre publique) [edit]


[modifier] Exemple

Demonstrates the risk of accessing non-existing elements via operator [].

#include <string>
#include <iostream>
#include <map>
 
int main()
{
    typedef std::map<std::string,int>  mapT;
 
    mapT my_map;
    my_map["first"]=  11;
    my_map["second"]= 23;
 
    mapT::iterator  it= my_map.find("first");
    if( it != my_map.end() ) std::cout << "A: " << it->second << "\n";
 
    it= my_map.find("third");
    if( it != my_map.end() ) std::cout << "B: " << it->second << "\n";
 
    // Accessing a non-existing element creates it
    if( my_map["third"] == 42 ) std::cout << "Oha!\n";
 
    it= my_map.find("third");
    if( it != my_map.end() ) std::cout << "C: " << it->second << "\n";
 
    return 0;
}

Résultat :

A: 11
C: 0