November 2016
Beginner to intermediate
816 pages
19h 58m
Japanese
Content preview from Cクイックリファレンス 第2版
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408
18
章 標準ライブラリ関数
FE_DOWNWARD
次に小さい整数に切り下げる。
FE_UPWARD
次に大きい整数に切り上げる。
FE_TONEAREST
最も近い整数に丸める。
FE_TOWARDZERO
正の値は切り下げ、負値は切り上げる。
関数は成功なら0を返す。非ゼロ戻り値はエラーが起こったことを示す。
■
例
/*
*
丸め方向の保存、設定、復元。
*
丸め方向の設定が失敗したらエラー報告。
*/
#pragma STDC FENV_ACCESS ON
int prev_rounding_dir = fegetround();
int result = fesetround(FE_TOWARDZERO);
/* ... 0
への丸めが必要な計算を実行
... */
fesetround(prev_rounding_dir);
#pragma STDC FENV_ACCESS OFF
本章の
fmod()
の例も参照。
■
参照
●
fegetround()
,
round()
,
lround()
,
llround()
,
nearbyint()
,
rint()
,
lrint()
,
llrint()
fetestexcept
C99
浮動小数点環境の状態フラグをビットマスクでテストする
#include <fenv.h>
int fetestexcept(int
excepts
);
fetestexcept()
関数は、浮動小数点例外フラグを表す fenv.hで定義したマクロの値の
ビット和を引数にとる。マクロは ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.