Date and time utilities

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C++
 
实用工具库
类型的支持 (basic types, RTTI, type traits)
动态内存管理
错误处理
程序实用工具
可变参数函数
日期和时间
函数对象
initializer_list（C++11）
bitset
hash（C++11）
关系运算符
Original:
Relational operators
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rel_ops::operator!=
rel_ops::operator>
rel_ops::operator<=
rel_ops::operator>=
双和元组
Original:
Pairs and tuples
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pair
tuple（C++11）
piecewise_construct_t（C++11）
piecewise_construct（C++11）
掉期，远期和移动
Original:
Swap, forward and move
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swap
forward（C++11）
move（C++11）
move_if_noexcept（C++11）
declval（C++11）
 
日期和时间工具
 
C + +支持两种类型的操作时间：
Original:
C++ includes support for two types of time manipulation:
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  • chrono图书馆，灵活的收集跟踪时间的类型，不同的精确度（例如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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  • C-风格的日期和时间库（例如std::time）
    Original:
    C-style date and time library (e.g. std::time)
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目录

[编辑] NJ库

chrono库定义了三种主要的类型（持续时间，时钟和时间点），以及实用的功能和常见的类型定义.
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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[编辑] 持续时间

持续时间的时间跨度，定义为一定数量的蜱一段时间的单位。例如，“42秒”可以表示的组成的持续时间中的42的一个1秒的时间单元蜱.
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）
一个时间间隔
Original:
a time interval
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（类模板） [edit]

[编辑] 时钟

一个时钟由一个起点（或时代）和时钟速率。例如，时钟可以有一个具有划时代意义的1970年1月1日，并勾选每一秒。 C + +定义了三种时钟方式：
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
（C++11）
从全系统的实时时钟，挂钟时间
Original:
wall clock time from the system-wide realtime clock
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（类） [edit]
（C++11）
单调时钟将永远不会被调整
Original:
monotonic clock that will never be adjusted
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（类） [edit]
（C++11）
的时钟用最短的剔期
Original:
the clock with the shortest tick period available
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（类） [edit]

[编辑] 时间点

时间点是一个持续的时间已经过去了时代的特定的时钟.
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
（C++11）
 a point in time
（类模板） [edit]

[编辑] C-风格的日期和时间库

本发明还提供C风格的日期和时间的函数，如std::time_t，std::difftime，和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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[编辑] 为例

这个例子显示一个函数调用的执行时间信息
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
来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/chrono&oldid=27316”