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
번호 | 분류 | 제목 | 글쓴이 | 날짜 | 조회 수 |
---|---|---|---|---|---|
1161 | Develop | GCM 사용하기 3 (JSP로 GCM 푸시 서버 만들기) 4 | hooni | 2013.07.06 | 25316 |
1160 | Develop | git 브런치 배우기 (링크) | hooni | 2013.07.09 | 20571 |
1159 | Develop | GPL, AGPL, MPL,.. 한눈에 보는 오픈소스SW 라이선스 | hooni | 2014.10.14 | 1146 |
1158 | Etc | GSM에서 음성이 실리는 과정 요약.. | hooni | 2013.04.23 | 17520 |
1157 | Etc | How to completely Uninstall Coda | hooni | 2017.10.24 | 2207 |
1156 | System/OS | How to Install and Use wget on Mac | hooni | 2020.09.03 | 1291 |
1155 | System/OS | How to Setup an Email Server on CentOS 7 | hooni | 2018.04.05 | 2792 |
1154 | Develop | How to Test SMTP AUTH using Telnet | hooni | 2018.04.05 | 1345 |
1153 | System/OS | HTTP 프로토콜 (브라우저와 웹서버 간의 통신) | hooni | 2003.04.23 | 48253 |
1152 | System/OS | HTTPS와 SSL 인증서 | hooni | 2014.03.11 | 7550 |
1151 | Etc | iOS 에서 쓸만한 오프라인 구글지도 찾기 | hooni | 2014.01.06 | 16039 |
1150 | Etc | IoT가 만드는 미래와 플랫폼 경쟁력 | hooni | 2014.09.23 | 0 |