NSMutableArray的addObject是直接加入pointer而不是copy一份進去

NSMutableArray *array = [NSMutableArray new];

NSNumber *number = [[NSNumber new];

For (int i = 0, i<10 , i++){

   number = [NSNumber numberWithInt:i];

   [array addObject:number];

}

這樣的結果會是

10

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10

10

10

10

10

10

10

10

NSMutableArray *array = [NSMutableArray new];

For (int i = 0, i<10 , i++){

   NSNumber *number = [[NSNumber new];

   number = [NSNumber numberWithInt:i];

   [array addObject:number];

}

而這樣的結果才會是

1

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10