Develop
2013.10.31 16:51
[ios] Random Thoughts: Rand() vs. arc4random()
조회 수 68115 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
번호 | 분류 | 제목 | 글쓴이 | 날짜 | 조회 수 |
---|---|---|---|---|---|
841 | Develop | [ios] 아이폰용 앱 오픈 소스들 | hooni | 2013.04.23 | 468728 |
840 | Develop | 자주 쓰는 Docker 명령어 alias | hooni | 2020.01.10 | 271324 |
839 | Develop | [ios] 언어, 지역, 국가 설정 가져오기 | hooni | 2014.05.12 | 271095 |
838 | Develop | [ios] Start developing your navigation app for CarPlay without enrollment | hooni | 2020.02.22 | 125282 |
837 | Develop | [android] 만화 어플 소스코드 | hooni | 2013.04.23 | 92917 |
836 | Develop | 레고 마인드스톰 NXT 수도쿠, 큐브 소스코드.. 20 | hooni | 2013.04.23 | 81554 |
835 | Develop | [c#] Hashtable <-> Json (dll 포함) | hooni | 2013.04.23 | 80719 |
834 | Develop | [C#] MD5, SHA1 해시 & 인코딩 | hooni | 2013.04.23 | 77951 |
833 | Develop | [android] 점심 해결 앱 소스 코드 ㅋㅋ | hooni | 2013.04.23 | 76475 |
832 | Develop | [json] 종결자 (설명과 웹, C/C++/C# 프로그램 샘플 코드) | hooni | 2013.04.23 | 72031 |
831 | Develop | [android] keytool을 사용하여 키스토어 생성 | hooni | 2013.04.23 | 69574 |
» | Develop | [ios] Random Thoughts: Rand() vs. arc4random() | hooni | 2013.10.31 | 68115 |