ios 自动排序（shuffle）密码键盘 实现算法

算法一

NSMutableArray *randSequence = [[NSMutableArray alloc] initWithCapacity:8]; for (int ii = 0; ii < 10; ++ii) [randSequence addObject:[NSNumber numberWithInt:ii]]; for (int ii = 9; ii > -1; --ii) { int r = arc4random() % 9 [randSequence exchangeObjectAtIndex:ii withObjectAtIndex:r]; 

算法二：

@interface NSMutableArray (Shuffling) - (void)shuffle; @end // NSMutableArray_Shuffling.m #import "NSMutableArray_Shuffling.h" @implementation NSMutableArray (Shuffling) - (void)shuffle { NSUInteger count = [self count]; for (NSUInteger i = 0; i < count; ++i) { // Select a random element between i and end of array to swap with. NSInteger nElements = count - i; NSInteger n = (arc4random() % nElements) + i; [self exchangeObjectAtIndex:i withObjectAtIndex:n]; } } @end