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std::map::find

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< cpp‎ | container‎ | map

 
 
 
std::map
Las funciones miembro
Original:
Member functions
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Elemento acceso
Original:
Element access
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Los iteradores
Original:
Iterators
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Capacidad
Original:
Capacity
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Modificadores
Original:
Modifiers
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Buscar
Original:
Lookup
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map::find
Los observadores
Original:
Observers
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iterator find( const Key& key );
const_iterator find( const Key& key ) const;
Busca un elemento con key clave.
Original:
Finds an element with key key.
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Contenido

[editar] Parámetros

key -
valor de la clave del elemento que desea buscar
Original:
key value of the element to search for
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[editar] Valor de retorno

Iterator a un elemento con key clave. Si no se encuentra dicho elemento, past-the-end (ver end()) iterador devuelto .
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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[editar] Complejidad

Logarithmic in the size of the container.

[editar] Ver también

devuelve el número de elementos coincidentes clave específica
Original:
returns the number of elements matching specific key
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(función miembro público) [editar]
El rendimiento es de los elementos que coinciden con una clave específica
Original:
returns range of elements matching a specific key
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(función miembro público) [editar]


[editar] Ejemplo

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;
}

Salida:

A: 11
C: 0