필요한 랜덤수의 개수를 담으면, 랜덤수를 담은 배열을 리턴하는 메소드

+ (NSArray*)makeRandomIndexArray:(NSUInteger)countOfIndices

{

srand(time(NULL));

NSMutableArray* indices = [[NSMutableArray alloc] initWithCapacity:countOfIndices];

NSMutableArray* tempArray = [[NSMutableArray alloc]initWithCapacity:countOfIndices];

for (NSUInteger i = 0; i < countOfIndices; i++) 

{

[tempArray addObject:[NSNumber numberWithInt:i]];

}

for (NSUInteger i = 0; i < countOfIndices; i++) 

{

NSUInteger randomNumber = (rand()% (countOfIndices-i) );

NSNumber* number = [tempArray objectAtIndex:randomNumber];

[indices addObject:number];

[tempArray removeObjectAtIndex:randomNumber];

}

[tempArray release];

return (NSArray*)[indices autorelease];

}