我想洗牌的我的应用程序一副牌，我用下面的code。这是否会充分随机甲板？我几乎可以肯定是会只是想另一种意见。谢谢！

 的for（int i = 0; I＆LT; 40000;我++）{
    INT randomInt1 = arc4random（）％[deck.cards计数]
    INT randomInt2 = arc4random（）％[deck.cards计数]
    [deck.cards exchangeObjectAtIndex：randomInt1 withObjectAtIndex：randomInt2]。
 

编辑：如果你想知道或者应该碰到过这样的未来。这是我已经与洗牌我的扑克牌，它是费雪耶茨算法的实现。我把它从后@MartinR建议低于它可以在这里找到：What's最好的方式来洗牌一个NSMutableArray？

  NSUInteger数= [deck.cards计数]
    对于（UINT I = 0; I＆LT;计数; ++ I）
    {
        //我和阵列交换与端之间选择一个随机元素。
        INT nElements =计数 - 我;
        INT N = arc4random_uniform（nElements）+ I;
        [deck.cards exchangeObjectAtIndex：我withObjectAtIndex：N];
    }
 

解决方案

您code应该相当不错，如果[deck.cards算上] LT; 40000，但下面是更好的。

 的for（int i = [deck.cards数]  -  1; I＆GT; 0;我 - ）{
    INT randomInt1 = arc4random_uniform第（i + 1）;
    [deck.cards exchangeObjectAtIndex：randomInt1 withObjectAtIndex：我]。
}
 

从文档：

arc4random_uniform（）将返回一个均匀分布的随机数   比UPPER_BOUND少。        arc4random_uniform（）建议在结构像``arc4random（）％UPPER_BOUND''，因为它避免了        模数偏差时的上限不是二的幂。

I am trying to shuffle a deck of cards in my app and I use the following code. Will this sufficiently randomize the deck? I am almost certain is will just want another opinion. Thanks!

for (int i = 0; i < 40000; i++) {
    int randomInt1 = arc4random() % [deck.cards count];
    int randomInt2 = arc4random() % [deck.cards count];
    [deck.cards exchangeObjectAtIndex:randomInt1 withObjectAtIndex:randomInt2];

EDIT: In case anyone is wondering or should come across this in the future. This is what I have gone with to shuffle my deck of cards, it is an implementation of the Fisher-Yates Algorithm. I got it from the post @MartinR suggested below which can be found here: What's the Best Way to Shuffle an NSMutableArray?

NSUInteger count = [deck.cards count];
    for (uint i = 0; i < count; ++i)
    {
        // Select a random element between i and end of array to swap with.
        int nElements = count - i;
        int n = arc4random_uniform(nElements) + i;
        [deck.cards exchangeObjectAtIndex:i withObjectAtIndex:n];
    }

Your code should work rather good if [deck.cards count] < 40000 but following is better

for (int i = [deck.cards count] - 1; i > 0 ; i--) {
    int randomInt1 = arc4random_uniform(i + 1);
    [deck.cards exchangeObjectAtIndex:randomInt1 withObjectAtIndex:i];
}

from docs:

arc4random_uniform() will return a uniformly distributed random number less than upper_bound. arc4random_uniform() is recommended over constructions like ``arc4random() % upper_bound'' as it avoids "modulo bias" when the upper bound is not a power of two.