Develop
2013.10.31 16:51
[ios] Random Thoughts: Rand() vs. arc4random()
조회 수 68125 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 |
---|---|---|---|---|---|
1173 | Develop | '2014 모바일 개발 트렌드' 발표자료입니다. | hooni | 2014.10.02 | 1140 |
1172 | System/OS | Apache CORS 설정 1 | hooni | 2020.09.04 | 2919 |
1171 | Develop | Aspect Oriented Programming in Objective-C | hooni | 2015.05.18 | 952 |
1170 | System/OS | asx미디어 정보 기록.. | hooni | 2003.04.23 | 20609 |
1169 | System/OS | CentOS 6.5 USB 설치 6 | hooni | 2013.12.18 | 37810 |
1168 | System/OS | CentOS 에서 Cacti 설치하기 | hooni | 2015.01.02 | 1943 |
1167 | System/OS | Configure Postfix to Use Gmail SMTP on Ubuntu 18.04 | hooni | 2020.02.07 | 1509 |
1166 | Develop | DDay Memo 1.9.4 소스코드 | hooni | 2015.10.03 | 0 |
1165 | Etc | EBS [수학영역] 미적분과 통계 기본 - 정규분포의 의미와 특징은? | hooni | 2015.04.20 | 1106 |
1164 | System/OS | Enable Safari Hidden Debug Menu in Mac OS X | hooni | 2017.02.07 | 1740 |
1163 | System/OS | Enable the Develop Menu in Safari | hooni | 2017.02.07 | 1342 |
1162 | Develop | GCM 사용하기 2 (단말에 GCM 구현하기) | hooni | 2013.07.06 | 23414 |