Develop
2013.10.31 16:51
[ios] Random Thoughts: Rand() vs. arc4random()
조회 수 68056 댓글 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
-
[ios] XCode에서 Provisioning Profile 여러개 중복될 때
-
알고리즘 성능 분석 기준
-
알고리즘 성능분석
-
[ios] iOS에서 디바이스 종류 알아오기
-
[ios] 아이폰 GPS 사용하기
-
[ios] 언어, 지역, 국가 설정 가져오기
-
[ios] URL 파라미터 파싱~
-
[ios] 앱 딜리게이트 얻어오기. (AppDelegate)
-
[ios] 앱딜리게이트 라이프사이클 (AppDelegate Lifecycle)
-
[ios] 애플 앱스토어 IDFA 리뷰 정책 변경 안내
-
[ios] NSString URL Encode/Decode (인코딩/디코딩)
-
[ios] 커스텀 폰트 사용하기 (Custom Fonts)