Develop
2013.10.31 16:51
[ios] Random Thoughts: Rand() vs. arc4random()
Views 68125 Comment 0
랜덤함수 사용시..
iOS
There are several built-in randomizers on the iPhone, and most people's first thought is to use rand() after seeding it by calling
srandom(time(NULL));
But... rand() is really not a very good PRNG. random() is a little better, but still less then ideal. Fortunately, these are not the only ones available on the iPhone. Personally, I like arc4random() because it's a decent pseudo-random algorithm and has twice the range or rand().
On the iPhone, RAND_MAX is 0x7fffffff (2147483647), while arc4random() will return a maximum value of 0x100000000 (4294967296), giving much more precision. You also don't need to seed arc4random(), as the first call to it automatically seeds it.
결론은 arc4random() 을 사용하자.
[출처] http://iphonedevelopment.blogspot.com/2008/10/random-thoughts-rand-vs-arc4random.html
No. | Category | Subject | Author | Date | Views |
---|---|---|---|---|---|
60 | System/OS | [mac] OS X 엘 캐피탄에서 Soudflower 사용하기 2 | hooni | 2016.10.03 | 1187 |
59 | System/OS | [mac] Mac OS에서 재생되는 사운드를 녹음하는 방법 | hooni | 2016.10.03 | 1749 |
58 | Develop | [c] Mac OS 에 gmp(gmp.h) 라이브러리 설치 | hooni | 2016.10.03 | 1452 |
57 | Develop | [ios][swift] 초간단 카달로그 앱 (Catalog App) | hooni | 2016.06.27 | 7461 |
56 | Develop | [ios] 웹뷰 history.back() ㅋㄷ | hooni | 2016.06.27 | 2048 |
55 | Develop | [ios] 기본 네비게이션바의 타이틀, back버튼 위치와 속성 변경 | hooni | 2016.05.16 | 2200 |
54 | Develop | [ios] UUID 생성 + Key Chain 연동 | hooni | 2016.05.13 | 4793 |
53 | Develop | [ios] Did UIScrollView End Scrolling? | hooni | 2016.04.19 | 1180 |
52 | Develop | [ios] NavigationController 에서 왼쪽(back) 버튼 후킹하기 | hooni | 2015.10.23 | 1306 |
51 | Develop | [ios] 언어, 지역, 국가 설정 가져오기 | hooni | 2014.05.12 | 272319 |
50 | Develop | [unix] 로그파일 정리 쉘스크립트 | hooni | 2014.02.19 | 10886 |
49 | Develop | [c] 64bit 머신에서 inet_ntoa() 사용시 Segment fault 대처 방법법 | hooni | 2014.02.08 | 14266 |