Namespace
Varianti

std::map::empty

Da cppreference.com.
< cpp‎ | container‎ | map

 
 
 
std::map
Membri funzioni
Original:
Member functions
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map::map
map::~map
map::operator=
map::get_allocator
Elemento accesso
Original:
Element access
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map::at
map::operator[]
Iteratori
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)
Capacità
Original:
Capacity
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map::empty
map::size
map::max_size
Modificatori
Original:
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
Osservatori
Original:
Observers
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map::key_comp
map::value_comp
 
bool empty() const;
Controlla se il contenitore non ha elementi, vale a dire se begin() == end().
Original:
Checks if the container has no elements, i.e. whether begin() == end().
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Indice

[modifica] Parametri

(Nessuno)
Original:
(none)
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[modifica] Valore di ritorno

true se il contenitore è vuoto, false altrimenti
Original:
true if the container is empty, false otherwise
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[modifica] Eccezioni

noexcept specification:  
noexcept
  (dal C++11)

[modifica] Complessità

Constant
Original:
Constant
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[modifica] Esempio

Il codice seguente utilizza empty per controllare se un std::map<int> contiene elementi:
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';
}

Output:

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

See also

restituisce il numero di elementi
Original:
returns the number of elements
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(membro pubblico funzione) [edit]