Develop
2013.10.31 16:51
[ios] Random Thoughts: Rand() vs. arc4random()
조회 수 78011 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 |
---|---|---|---|---|---|
267 | Develop | [java] Sieve of Eratosthenes (에라토스테네스의 체) | hooni | 2013.04.23 | 10464 |
266 | Develop |
[java] 거스름돈 계산.. swing 사용
![]() |
hooni | 2013.04.23 | 10657 |
265 | Develop |
[java] 그래픽(도형,다각형..) 이동,확대,축소,회전에 대한 내용..
1 ![]() |
hooni | 2013.04.23 | 9886 |
264 | Develop | [java] 날짜 계산 (Date, SimpleDateFormat) | hooni | 2013.04.23 | 13017 |
263 | Develop |
[java] 마우스 버튼 테스트.. swing..
![]() |
hooni | 2013.04.23 | 9109 |
262 | Develop |
[java] 메모패드.. 스윙(swing)으로..
![]() |
hooni | 2013.04.23 | 9370 |
261 | Develop |
[java] 스윙(swing) 인터페이스 이용해서 만든 구구단.. ㅋㅋ
![]() |
hooni | 2003.04.23 | 8177 |
260 | Develop |
[java] 스윙(swing)버튼 테스트 ㅋㅋ
![]() |
hooni | 2013.04.23 | 10310 |
259 | Develop |
[java] 스트러츠(Struts) 세팅 ㅋㅋ
![]() |
hooni | 2013.04.23 | 44336 |
258 | Develop |
[java] 에디터.. swing 사용
![]() |
hooni | 2013.04.23 | 7506 |
257 | Develop |
[java] 입출력 스트림 1부 (문자)
![]() |
hooni | 2013.04.23 | 18154 |
256 | Develop |
[java] 입출력 스트림 2부 (바이트)
![]() |
hooni | 2013.04.23 | 11261 |