新手,请大家帮忙解答一下,不甚感激
NSArray *arr = [NSArray arrayWithObjects:@"1",@"2", nil];
NSLog(@"%zi",[arr indexOfObject:@"2"]);//计数为1
NSString *str = [[NSString alloc]init];
NSArray *arry = [[NSArray alloc]init];
NSLog(@"%zi",(unsigned long)[str retainCount]);//计数为-1
NSLog(@"%zi",(unsigned long)[arry retainCount]);//计数为2
这是怎么回事啊