std::vector::front

 

C++

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std::vector

Член функций 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.

vector::vector

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Элемент доступа 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.

vector::at

vector::operator[]

vector::front

vector::back

vector::data (C++11)

Итераторы Original: Iterators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

vector::begin vector::cbegin (C++11)

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Потенциала Original: Capacity The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

vector::empty

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reference front();
const_reference front() const;

Возвращает ссылку на первый элемент в контейнере.

Original:

Returns a reference to the first element in the container.

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Вызов front на пустой контейнер не определен.

Original:

Calling front on an empty container is undefined.

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Параметры

(Нет)

Original:

(none)

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Возвращаемое значение

ссылка на первый элемент

Original:

reference to the first element

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Сложность

Constant

Original:

Constant

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Notes

Для контейнера c, выражение c.front() эквивалентно *c.begin().

Original:

For a container c, the expression c.front() is equivalent to *c.begin().

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Пример

Следующий код использует front, чтобы отобразить первый элемент std::vector<char>

Original:

The following code uses front to display the first element of a std::vector<char>:

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#include <vector>
#include <iostream>
 
int main()
{
    std::vector<char> letters {'o', 'm', 'g', 'w', 't', 'f'};
 
    if (!letters.empty()) {
        std::cout << "The first character is: " << letters.front() << '\n';
    }
}

Вывод:

The first character is o

See also

back	предоставляет доступ к последнему элементу (public функция-член)