std::map::empty

 

C++

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Recipientes biblioteca

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

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std::map

Funções de membro 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

acesso. Elemento 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[]

Iteradores 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)

Capacidade 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

Modificadores 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

Pesquisa 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

Observadores 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

 

bool empty()const;

Verifica se o recipiente não tem elementos, ou seja, se begin()== end().

Original:

Checks if the container has no elements, i.e. whether begin()== end().

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Parâmetros

(Nenhum)

Original:

(none)

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Valor de retorno

true se o recipiente estiver vazio, false contrário

Original:

true if the container is empty, false otherwise

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Exceções

noexcept specification:  

noexcept

  (desde C++11)

Complexidade

Constante

Original:

Constant

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Exemplo

O código a seguir usa empty para verificar se um std::map<int> contém quaisquer elementos:

Original:

The following code uses empty to check if a std::map<int> contains any elements:

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#include <map>#include <iostream>   int main(){std::map<int> numbers;std::cout<<"Initially, numbers.empty(): "<< numbers.empty()<<'\n';   numbers.push_back(42); numbers.push_back(13317);std::cout<<"After adding elements, numbers.empty(): "<< numbers.empty()<<'\n';}

Saída:

Initially, numbers.empty(): 1 After adding elements, numbers.empty(): 0

See also

size	devolve o número de elementos Original: returns the number of elements 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)