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std::nearbyint

提供: cppreference.com
< cpp‎ | numeric‎ | math

 
 
ニューメリックスライブラリ
一般的な数学関数
浮動小数点環境
複素数
数値配列
擬似乱数生成
コンパイル時有理数演算 (C++11)
汎用の数値演算
Original:
Generic numeric operations
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iota(C++11)
accumulate
inner_product
adjacent_difference
partial_sum
 
一般的な数学関数
機能します
Original:
Functions
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基本操作
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Basic operations
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remainder(C++11)
remquo(C++11)
fma(C++11)
fmax(C++11)
fmin(C++11)
fdim(C++11)
nan
nanf
nanl
(C++11)
(C++11)
(C++11)
指数関数
Original:
Exponential functions
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exp
exp2(C++11)
expm1(C++11)
log
log10
log1p(C++11)
log2(C++11)
電源機能
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Power functions
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sqrt
cbrt(C++11)
hypot(C++11)
pow
三角関数や双曲線関数
Original:
Trigonometric and hyperbolic functions
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sinh
cosh
tanh
asinh(C++11)
acosh(C++11)
atanh(C++11)
エラーおよびガンマ関数
Original:
Error and gamma functions
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erf(C++11)
erfc(C++11)
lgamma(C++11)
tgamma(C++11)
最も近い整数の浮動小数点演算
Original:
Nearest integer floating point operations
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ceil
floor
round
lround
llround
(C++11)
(C++11)
(C++11)
trunc(C++11)
nearbyint(C++11)
rint
lrint
llrint
(C++11)
(C++11)
(C++11)
点操作関数に浮かぶ
Original:
Floating point manipulation functions
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ldexp
scalbn
scalbln
(C++11)
(C++11)
ilogb(C++11)
logb(C++11)
frexp
modf
nextafter
nexttoward
(C++11)
(C++11)
copysign(C++11)
分類/比較
Original:
Classification/Comparison
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fpclassify(C++11)
isfinite(C++11)
isinf(C++11)
isnan(C++11)
isnormal(C++11)
signbit(C++11)
isgreater(C++11)
isgreaterequal(C++11)
isless(C++11)
islessequal(C++11)
islessgreater(C++11)
isunordered(C++11)
マクロ定数
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Macro constants
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FP_NORMAL
FP_SUBNORMAL
FP_ZERO
FP_INFINITE
FP_NAN
(C++11)
(C++11)
(C++11)
(C++11)
(C++11)
 
Defined in header <cmath>
float       nearbyint( float arg );
(C++11およびそれ以降)
double      nearbyint( double arg );
(C++11およびそれ以降)
long double nearbyint( long double arg );
(C++11およびそれ以降)
double      nearbyint( Integral arg );
(C++11およびそれ以降)
浮動小数点形式の整数値に丸め浮動小数点引数arg、現在の丸めモードを使用して.
Original:
Rounds the floating-point argument arg to an integer value in floating-point format, using the current rounding mode.
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目次

[編集] パラメータ

arg -
浮動小数点値
Original:
floating point value
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[編集] 値を返します

丸めargの整数の結果
Original:
The integer result of rounding arg
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[編集] ノート

唯一の違いstd::nearbyintstd::rintstd::rintがそれを発生させたことがないながらFE_INEXACTは、std::nearbyint浮動小数点の例外を発生させるかもしれないということです.
Original:
The only difference between std::nearbyint and std::rint is that std::rint may raise the FE_INEXACT floating-point exception, while std::nearbyint never raises it.
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[編集]

[edit]
#include <cmath>
#include <cfenv>
#include <iostream>
 
int main()
{
    #pragma STDC FENV_ACCESS ON
    std::fesetround(FE_DOWNWARD);
    std::cout << "rounding using FE_DOWNWARD: \n" << std::fixed
              << " 12.0 ->  " << std::nearbyint(12.0) << '\n'
              << " 12.1 ->  " << std::nearbyint(12.1) << '\n'
              << "-12.1 -> " << std::nearbyint(-12.1) << '\n'
              << " 12.5 ->  " << std::nearbyint(12.5) << '\n'
              << " 12.9 ->  " << std::nearbyint(12.9) << '\n'
              << "-12.9 -> " << std::nearbyint(-12.9) << '\n'
              << " 13.0 ->  " << std::nearbyint(13.0) << '\n';
    std::fesetround(FE_TONEAREST);
    std::cout << "rounding using FE_TONEAREST: \n"
              << " 12.0 ->  " << std::nearbyint(12.0) << '\n'
              << " 12.1 ->  " << std::nearbyint(12.1) << '\n'
              << "-12.1 -> " << std::nearbyint(-12.1) << '\n'
              << " 12.5 ->  " << std::nearbyint(12.5) << '\n'
              << " 12.9 ->  " << std::nearbyint(12.9) << '\n'
              << "-12.9 -> " << std::nearbyint(-12.9) << '\n'
              << " 13.0 ->  " << std::nearbyint(13.0) << '\n';
}

Output:

rounding using FE_DOWNWARD:
 12.0 ->  12.000000
 12.1 ->  12.000000
-12.1 -> -13.000000
 12.5 ->  12.000000
 12.9 ->  12.000000
-12.9 -> -13.000000
 13.0 ->  13.000000
rounding using FE_TONEAREST: 
 12.0 ->  12.000000
 12.1 ->  12.000000
-12.1 -> -12.000000
 12.5 ->  12.000000
 12.9 ->  13.000000
-12.9 -> -13.000000
 13.0 ->  13.000000

[編集] も参照してください

(C++11)
(C++11)
(C++11)
結果が異なる場合
を除いて、現在の丸めモードを使用して、最も近い整数
Original:
nearest integer using current rounding mode with
exception if the result differs
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(関数) [edit]
(C++11)
(C++11)
(C++11)
最も近い整数値、中間値の場合でゼロから離れる丸め
Original:
nearest integer, rounding away from zero in halfway cases
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(関数) [edit]
(C++11)
(C++11)
丸め方向を取得または設定します
Original:
gets or sets rounding direction
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(関数) [edit]