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    std::map::find

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    <metanoindex/>

     
    C++
     
    Container-Bibliothek
     
    std::map
    Member-Funktionen
    Original:
    Member functions
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    map::map
    map::~map
    map::operator=
    map::get_allocator
    Elementzugriff zerstört
    Original:
    Element access
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    map::at
    map::operator[]
    Iteratoren
    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)
    Kapazität
    Original:
    Capacity
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    map::empty
    map::size
    map::max_size
    Modifiers
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    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
    Beobachter
    Original:
    Observers
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    map::key_comp
    map::value_comp
     
    <tbody> </tbody>
    iterator find( const Key& key );
    const_iterator find( const Key& key ) const;
    Sucht ein Element mit Schlüssel key.
    Original:
    Finds an element with key key.
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    Parameter

    key -
    Schlüsselwert des Elements zu suchen
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    key value of the element to search for
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    Rückgabewert

    Iterator auf ein Element mit Schlüssel key. Wenn kein solches Element gefunden wird, past-the-Ende (siehe end()) Iterator zurückgegeben .
    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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    Komplexität

    Logarithmic in the size of the container.

    Siehe auch
    liefert die Anzahl der Elemente zu einem Schlüssel
    Original:
    returns the number of elements matching specific key
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    (öffentliche Elementfunktion) [edit]
    Bandbreite der Rendite von Elementen übereinstimmenden eine bestimmte Taste
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    returns range of elements matching a specific key
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    (öffentliche Elementfunktion) [edit]


    Beispiel

    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;
}

    Output: 

    A: 11
C: 0