Develop
2013.10.31 16:51
[ios] Random Thoughts: Rand() vs. arc4random()
Views 68112 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 |
---|---|---|---|---|---|
13 | Develop |
[ios] UUID 생성 + Key Chain 연동
![]() |
hooni | 2016.05.13 | 4771 |
12 | Develop |
[ios] 기본 네비게이션바의 타이틀, back버튼 위치와 속성 변경
![]() |
hooni | 2016.05.16 | 2185 |
11 | Develop |
[ios] 웹뷰 history.back() ㅋㄷ
![]() |
hooni | 2016.06.27 | 2018 |
10 | Develop |
[ios][swift] 초간단 TableView 샘플
![]() |
hooni | 2016.06.27 | 844 |
9 | Develop |
[ios][swift] 초간단 To-do Memo
![]() |
hooni | 2016.06.27 | 1176 |
8 | Develop |
[ios][swift] 초간단 카달로그 앱 (Catalog App)
![]() |
hooni | 2016.06.27 | 7277 |
7 | Develop |
[ios] 동영상 플레이어 샘플 (for Local File)
![]() |
hooni | 2017.02.07 | 1189 |
6 | Develop |
[ios] 동영상 플레이어 샘플 (for Remote Url)
![]() |
hooni | 2017.02.07 | 1735 |
5 | Develop |
[ios] Facebook Cache 갱신하는 함수
![]() |
hooni | 2017.02.27 | 1305 |
4 | Develop |
[ios] 동영상 플레이어 샘플 (for PIP Player)
![]() |
hooni | 2017.03.15 | 1392 |
3 | Develop | [ios] NSString, RegularExpression Find/Replace | hooni | 2017.04.14 | 933 |
2 | Develop |
[ios] Facebook SDK 로그인 설명
![]() |
hooni | 2017.04.19 | 1298 |