向ArrayList对象中添加一个元素的方法是 A: addObject(Object c) B: add(Object o) C: set(Object c) D: setObject(Object o)t

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2022-06-19 问题

向ArrayList对象中添加一个元素的方法是 A: addObject(Object c) B: add(Object o) C: set(Object c) D: setObject(Object o)t

2022-06-16 问题

NSMutableDictionary *mutableDic = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"lisi",@"name",[NSNumber numberWithInt:20],@"age", nil]; [mutableDic setObject:@"89" forKey:@"num"]; NSLog(@"mutableDic4 = %@“,mutableDic); 控制台打印是: A: name = lisi;num = 89 B: age = 20;name = lisi;num = 89 C: age = 20;name = lisi D: age = 20

NSMutableDictionary *mutableDic = [NSMutableDictionary dictionaryWithObjectsAndKeys:@"lisi",@"name",[NSNumber numberWithInt:20],@"age", nil]; [mutableDic setObject:@"89" forKey:@"num"]; NSLog(@"mutableDic4 = %@“,mutableDic); 控制台打印是: A: name = lisi;num = 89 B: age = 20;name = lisi;num = 89 C: age = 20;name = lisi D: age = 20