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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338
18
章 標準ライブラリ関数
asctime
日付と時刻構造体を文字列形式に変換する
#include <time.h>
char* asctime(struct tm*
systime
);
asctime()
関数の単一引数は構造体型
struct tm
へのポインタで、構造体の要素は年、月、
日、時などの日付と時刻。構造体は本章の
mktime()
で述べる。
asctime()
関数はタイムス
タンプ形式で日付と時刻を含む26バイトの静的文字列へのポインタを返す。
"Wed Apr 13 07:23:20 2005\n"
曜日と月は英語名の頭3文字で略され、ピリオドは付かない。月の日付が1 桁なら、10
の桁を空白で埋める。時が 9以下なら、0を頭に付ける。関数
strftime()
では書式指定文
字列を使ったより柔軟な日付と時刻出力ができる。
■
例
time_t now = {0};
time(&now); /*
時刻を求める（
1970
年
1
月
1
日からの秒数）
*/
printf("Date: %.24s GMT\n", asctime(gmtime(&now)));
典型的出力
Date: Sun Aug 28 14:22:05 2005 GMT
■
参照
●
localtime()
,
localtime_s()
,
gmtime()
,
gmtime_s()
,
ctime()
,
ctime_s()
,
difftime()
,
mktime()
,
strftime()
,
time()
●
localtime()
,
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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.