std::map::find

 

C++

Linguaggio

Concetti

Libreria di Utilità

Stringhe

Contenitori

Algoritmi

Iteratori

Libreria matematca

Input/output

Localizzazione

Espressioni regolari(C++11)

Operazioni atomicche(C++11)

Multithreading(C++11)

 

Contenitori libreria

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

priority_queue

 

std::map

Membri funzioni Original: Member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::map

map::~map

map::operator=

map::get_allocator

Elemento accesso Original: Element access The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::at

map::operator[]

Iteratori Original: Iterators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::begin map::cbegin (C++11)

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

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

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

Capacità Original: Capacity The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::empty

map::size

map::max_size

Modificatori Original: Modifiers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::clear

map::insert

map::emplace (C++11)

map::emplace_hint (C++11)

map::erase

map::swap

Lookup Original: Lookup The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::count

map::find

map::equal_range

map::lower_bound

map::upper_bound

Osservatori Original: Observers The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

map::key_comp

map::value_comp

 

iterator find(const Key& key );
const_iterator find(const Key& key )const;

Trova un elemento con key chiave.

Original:

Finds an element with key key.

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Parametri

key

-

valore della chiave dell'elemento da cercare Original: key value of the element to search for The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

Valore di ritorno

Iterator di un elemento con key chiave. Se tale elemento non viene trovato, past-the-end (vedi end()) iteratore viene restituito.

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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Complessità

Logarithmic in the size of the container.

Vedi anche

mihai are mere

count	restituisce il numero di elementi corrispondenti chiave specifica Original: returns the number of elements matching specific key The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (metodo pubblico)

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

#include <string>#include <iostream>#include <map>   int main(){typedefstd::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 itif( my_map["third"]==42)std::cout<<"Oha!\n";   it= my_map.find("third");if( it != my_map.end())std::cout<<"C: "<< it->second <<"\n";   return0;}

Output:

A: 11 C: 0