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Date and time utilities

Da cppreference.com.
< cpp


 
 
Utilità libreria
Tipo di supporto (basic types, RTTI, type traits)
Gestione della memoria dinamica
La gestione degli errori
Programma di utilità
Funzioni variadic
Data e ora
Funzione oggetti
initializer_list(C++11)
bitset
hash(C++11)
Gli operatori relazionali
Original:
Relational operators
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rel_ops::operator!=
rel_ops::operator>
rel_ops::operator<=
rel_ops::operator>=
Coppie e tuple
Original:
Pairs and tuples
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pair
tuple(C++11)
piecewise_construct_t(C++11)
piecewise_construct(C++11)
Swap, in avanti e spostare
Original:
Swap, forward and move
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swap
forward(C++11)
move(C++11)
move_if_noexcept(C++11)
declval(C++11)
 
Data e ora utilità
 
C++ include il supporto per due tipi di manipolazione del tempo:
Original:
C++ includes support for two types of time manipulation:
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  • La libreria chrono ,che é un insieme flessibile di tipi che tengono traccia del tempo con vari gradi di precisione (ad esempio std::chrono::time_point).
    Original:
    The chrono library, a flexible collection of types that track time with varying degrees of precision (e.g. std::chrono::time_point).
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  • La libreria in stile C per gestire data e ora (ad esempio std::time)
    Original:
    C-style date and time library (e.g. std::time)
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Indice

[modifica] NJ libreria

La libreria chrono definisce tre tipi principali (durata, orologi, e punti di tempo), nonché le funzioni di utilità e typedef comuni.
Original:
The chrono library defines three main types (durations, clocks, and time points) as well as utility functions and common typedefs.
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[modifica] Durata

Una durata consiste in un arco di tempo, definito come un certo numero di tick di qualche unità di tempo. Per esempio, "42 secondi" potrebbe essere rappresentato da una durata composta da 42 tick di un 1 secondo.
Original:
A duration consists of a span of time, defined as some number of ticks of some time unit. For example, "42 seconds" could be represented by a duration consisting of 42 ticks of a 1-second time unit.
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Defined in header <chrono>
Defined in namespace std::chrono
(C++11)
un intervallo di tempo
Original:
a time interval
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(classe template) [edit]

[modifica] Orologi

Un orologio è composto da un punto di partenza (o epoca) e un periodo di tick. Ad esempio, un orologio può avere un epoca al 1 ° gennaio 1970 e tick ogni secondo. C++ definisce tre tipi di clock:
Original:
A clock consists of a starting point (or epoch) and a tick rate. For example, a clock may have an epoch of January 1, 1970 and tick every second. C++ defines three clock types:
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Defined in header <chrono>
Defined in namespace std::chrono
orologio da parete dal livello di sistema orologio in tempo reale
Original:
wall clock time from the system-wide realtime clock
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(classe) [edit]
orologio monotona che non verrà mai modificato
Original:
monotonic clock that will never be adjusted
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(classe) [edit]
l'orologio con il più breve periodo di zecca disponibili
Original:
the clock with the shortest tick period available
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(classe) [edit]

[modifica] Punto nel tempo

Un punto nel tempo è un periodo di tempo che è passato dell'epoca specificata nell'orologio .
Original:
A time point is a duration of time that has passed since the epoch of specific clock.
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Defined in header <chrono>
Defined in namespace std::chrono
a point in time
(classe template) [edit]

[modifica] C-stile di data e ora libreria

Ci sono anche le funzioni in C-stile per gestire data e ora, come std::time_t, std::difftime e CLOCKS_PER_SEC.
Original:
Also provided are the C-style date and time functions, such as std::time_t, std::difftime, and CLOCKS_PER_SEC.
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[modifica] Esempio

In questo esempio vengono visualizzate informazioni sul tempo di esecuzione di una chiamata di funzione:
Original:
This example displays information about the execution time of a function call:
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#include <iostream>
#include <chrono>
#include <ctime>
 
int fibonacci(int n)
{
    if (n < 3) return 1;
    return fibonacci(n-1) + fibonacci(n-2);
}
 
int main()
{
    std::chrono::time_point<std::chrono::system_clock> start, end;
    start = std::chrono::system_clock::now();
    int result = fibonacci(42);
    end = std::chrono::system_clock::now();
 
    int elapsed_seconds = std::chrono::duration_cast<std::chrono::seconds>
                             (end-start).count();
    std::time_t end_time = std::chrono::system_clock::to_time_t(end);
 
    std::cout << "finished computation at " << std::ctime(&end_time)
              << "elapsed time: " << elapsed_seconds << "s\n";
}

Possible output:

finished computation at Sat Jun 16 20:42:57 2012
elapsed time: 3s