Develop
2013.10.31 16:51
[ios] Random Thoughts: Rand() vs. arc4random()
Views 68128 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] 기본 네비게이션바의 타이틀, back버튼 위치와 속성 변경 | hooni | 2016.05.16 | 2206 |
12 | Develop | [ios] UUID 생성 + Key Chain 연동 | hooni | 2016.05.13 | 4801 |
11 | Develop | [ios][swift] 초간단 카달로그 앱 (Catalog App) | hooni | 2016.06.27 | 7461 |
10 | Develop | [iphone] 아이폰 어플 모음 ㅋㅋ | hooni | 2013.04.23 | 13707 |
9 | Develop | [doc] Json Framework 설치와 사용 | hooni | 2013.04.23 | 21963 |
8 | Develop | [ios] iOS 6.0 이상 회전 하기 (이전 버전과 비교 변경 부분) | hooni | 2014.01.27 | 34247 |
7 | Develop | [ios] iOS 4.0 beta 에서 3.1.3으로 다운그레이드 하는 법 | hooni | 2013.04.23 | 37545 |
6 | Develop | [ios] 미스터피자(Mr.pizza) 어플 | hooni | 2013.04.23 | 42698 |
5 | Develop | [ios] 배열(NSArray) 연산과 간단한 애니메이션(split images) | hooni | 2013.10.31 | 45602 |
4 | Develop | [ios] UIAlertView 초간단 샘플 ㅎㅎ | hooni | 2013.10.14 | 46208 |
» | Develop | [ios] Random Thoughts: Rand() vs. arc4random() | hooni | 2013.10.31 | 68128 |
2 | Develop | [ios] 언어, 지역, 국가 설정 가져오기 | hooni | 2014.05.12 | 272402 |