std::chrono::duration_cast

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Gli operatori relazionali Original: Relational operators The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

rel_ops::operator!= rel_ops::operator> rel_ops::operator<= rel_ops::operator>=

Coppie e tuple Original: Pairs and tuples The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

pair

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Swap, in avanti e spostare Original: Swap, forward and move The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

swap

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Data e ora utilità

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duration (C++11)

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std::chrono::duration

Membri funzioni 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.

duration::duration

duration::operator=

duration::count

duration::zero

duration::min

duration::max

duration::operator+ duration::operator-

duration::operator++ duration::operator--

duration::operator+= duration::operator-= duration::operator*= duration::operator/= duration::operator%=

Non membri funzioni Original: Non-member functions The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

common_type

operator+ operator- operator* operator/ operator%

operator== operator!= operator< operator<= operator> operator>=

duration_cast

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

treat_as_floating_point

duration_values

 

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template <class ToDuration, class Rep, class Period> constexpr ToDuration duration_cast(const duration<Rep,Period>& d);		(dal C++11)

Converte un std::chrono::duration per una durata di ToDuration tipo diverso.

Original:

Converts a std::chrono::duration to a duration of different type ToDuration.

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Conversioni implicite non sono utilizzati. Moltiplicazioni e divisioni vengono evitate quando possibile, se è noto al momento della compilazione che uno o più parametri sono 1. I calcoli sono fatti nel più ampio tipo disponibile e convertito nel tipo di risultato solo quando hai finito.

Original:

No implicit conversions are used. Multiplications and divisions are avoided where possible, if it is known at compile time that one or more parameters are 1. Computations are done in the widest type available and converted to the result type only when finished.

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Parametri

d

-

durata da convertire Original: duration to convert The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions.

Valore di ritorno

d convertito in una durata di ToDuration tipo.

Original:

d converted to a duration of type ToDuration.

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Note

La funzione non prende parte alla risoluzione di sovraccarico a meno ToDuration è un'istanza di std::chrono::duration.

Original:

The function does not participate in the overload resolution unless ToDuration is an instance of std::chrono::duration.

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Fusione tra virgola mobile o tra durate durate interi in cui il periodo di sorgente è esattamente divisibile per il periodo di destinazione (ad esempio, ora a minuti) può essere eseguita implicitamente, non duration_cast è necessaria.

Original:

Casting between floating-point durations or between integer durations where the source period is exactly divisible by the target period (e.g. hours to minutes) can be performed implicitamente, no duration_cast is needed.

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Esempio

Questo esempio misura il tempo di esecuzione di una funzione

Original:

This example measures the execution time of a function

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#include <iostream>
#include <chrono>
#include <thread>

void f()
{
    std::this_thread::sleep_for(std::chrono::seconds(1));
}

int main()
{
    auto t1 = std::chrono::high_resolution_clock::now();
    f();
    auto t2 = std::chrono::high_resolution_clock::now();
    std::cout << "f() took "
              << std::chrono::duration_cast<std::chrono::milliseconds>(t2-t1).count()
              << " milliseconds\n";
}

Output:

f() took 1000 milliseconds