随机分配数组重复值
代码实现随机分配NSMuttable Array，但是随机分配之后数组一直重复同一个值，我怎么修改能让他不再重复了？在ios6中。
words = [[NSMutableArray alloc] initWithObjects:@"1", @"2", @"3",@"4", nil] ;
NSUInteger count = [words count];
for (int i = 0; i < count; i++)
{
NSInteger nElements = count - i;
NSInteger n = (arc4random() % nElements) + i;
NSLog(@"n val %d i val %d",i,n);
[words exchangeObjectAtIndex:i withObjectAtIndex:n];
}NSlog输出：
2012-12-31 12:49:05.730 quizer[1607:c07] n val 0 i val 0
2012-12-31 12:49:05.731 quizer[1607:c07] n val 1 i val 3
2012-12-31 12:49:05.731 quizer[1607:c07] n val 2 i val 2
2012-12-31 12:49:05.732 quizer[1607:c07] n val 3 i val 3
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随机分配数组包括0到TOTAL_NUMBER中的所有数值，都只一次。
@synthesize alreadyGeneratedNumbers;//this is a mutableArray. int TOTAL_NUMBER=5;//size of array -(int)generateRandomNumber{ int low_bound = 0; int high_bound = TOTAL_NUMBER; int width = high_bound - low_bound; int randomNumber = low_bound + arc4random() % width; return randomNumber; } -(IBAction)randomNumbers:(UIButton *)sender { NSMutableArray *startArray=[NSMutableArray arrayWithObjects:@"1",@"2",@"3",@"4",@"5", nil]; NSMutableArray *shuffle = [NSMutableArray new]; BOOL contains=YES; while ([shuffle count]<5) { NSNumber *generatedNumber=[NSNumber numberWithInt:[self generateRandomNumber]]; //NSLog(@"->%@",generatedNumber); if (![alreadyGeneratedNumbers containsObject:generatedNumber]) { [shuffle addObject:generatedNumber]; contains=NO; [alreadyGeneratedNumbers addObject:generatedNumber]; } } if ([alreadyGeneratedNumbers count] >= TOTAL_NUMBER) { NSLog(@"\nOne shuffel ended.....what to reshuffle"); [alreadyGeneratedNumbers removeAllObjects]; } NSMutableArray *shuffledArray=[NSMutableArray new]; for (NSNumber *index in shuffle) { [shuffledArray addObject:[startArray objectAtIndex:[index integerValue]]]; } NSLog(@"Shuffled array = %@",shuffledArray); }2019-07-17 19:15:28赞同 展开评论 打赏
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