std::map::find - cppreference.com
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      std::map::find

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      <metanoindex/>

       
      C++
       
      Recipientes biblioteca
       
      std::map
      Funções de membro
      Original:
      Member functions
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      map::map
      map::~map
      map::operator=
      map::get_allocator
      acesso. Elemento
      Original:
      Element access
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      map::at
      map::operator[]
      Iteradores
      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)
      Capacidade
      Original:
      Capacity
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      map::empty
      map::size
      map::max_size
      Modificadores
      Original:
      Modifiers
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      map::clear
      map::insert
      map::emplace(C++11)
      map::emplace_hint(C++11)
      map::erase
      map::swap
      Pesquisa
      Original:
      Lookup
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      map::count
      map::find
      map::equal_range
      map::lower_bound
      map::upper_bound
      Observadores
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      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;
      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
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      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.
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      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


      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: 

      A: 11
C: 0