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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61
5
章
式と演算子
式は定数、識別子、演算子の列で、指定された演算を行って評価する。プログラムにお
ける式の目的は、結果の値を得ること、または評価の副作用を生み出すこと、あるいは両
方（「5.1.3副作用と副作用完了点」参照）だ。
1つの定数、文字列リテラル、オブジェクトまたは関数の識別子は、それ自体で式だ。そ
のような単純な式または括弧で括られたより複雑な式が基本式と呼ばれる。C11標準は、
次節で述べる総称選択を基本式に追加した。
すべての式は型を持つ。式の型は式が評価された結果の値の型である。式が値を持たな
ければ、型
void
である。式の簡単な例を表5-1に示す（
a
が型
int
、
z
が型
float _Complex
の変数とする）。
表5-1 式の例
式 型
'\n' int
a + 1 int
a + 1.0 double
a < 77.7 int
"A string literal." char*
abort() void
sqrt(2.0) double
z / sqrt(2.0) double _Complex
表5-1の最後の項目からわかるように、複合式は式をオペランドにとる演算子で作られ
る。オペランドそのものは基本式でも複合式でもよい。例えば、関数呼び出しを乗算の要
素に使える。関数呼び出しの引数も、次の例のように、複数の演算子を含む式が使える。
2.0 * sin(3.14159 * fAngleDegrees/180.0)
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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.