std::map::find - cppreference.com

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`iterator find( const Key& key );`

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

Localiza um elemento com key chave.

Original:

Finds an element with key key.

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Parâmetros

key

valor chave do elemento para pesquisar

Original:

key value of the element to search for

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Valor de retorno

Iterador para um elemento com key chave. Se nenhum elemento for encontrado, past-the-end (ver end()) iterador é devolvido.

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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Complexidade

Logarithmic in the size of the container.

Veja também


	devolve o número de elementos correspondentes chave específica 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. (função pública membro) [edit]

	retorna a escala de elementos que combinam com uma tecla específica Original: returns range of elements matching a specific key The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. (função pública membro) [edit]

Exemplo

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;
}

Saída: