代码清单18-2 数组操作

Objective-C内存管理

最新推荐文章于 2025-08-30 17:45:03 发布

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本文演示了如何使用Objective-C创建并操作NSMutableArray对象，并通过一个具体的示例展示了当对可变数组内的对象进行修改时，原始数组及其副本的变化情况。揭示了Objective-C中对象引用的工作原理。

NSMutableArray *dataArray = [NSMutableArray arrayWithObjects:
            [NSMutableString stringWithString: @"one"],
            [NSMutableString stringWithString: @"two"],
            [NSMutableString stringWithString: @"three"],
            Nil
        ];
        NSMutableArray *dataArray2;
        NSMutableString *mStr;
        
        NSLog(@"dataArray: ");
        for(NSString *elem in dataArray)
            NSLog(@"   %@", elem);
        
        //复制一份，然后删除副本的第一个元素
        dataArray2 = [dataArray mutableCopy];
        mStr = [dataArray objectAtIndex: 0];
        [mStr appendString: @"ONE"];
        
        NSLog(@"dataArray:   ");
        for(NSString *elem in dataArray)
            NSLog(@"   %@", elem);
        
        NSLog(@"dataArray2:   ");
        for(NSString *elem in dataArray2)
            NSLog(@"   %@", elem);

2013-11-14 20:43:20.248 prog2[3503:303] dataArray:

2013-11-14 20:43:20.249 prog2[3503:303] one

2013-11-14 20:43:20.249 prog2[3503:303] two

2013-11-14 20:43:20.250 prog2[3503:303] three

2013-11-14 20:43:20.250 prog2[3503:303] dataArray:

2013-11-14 20:43:20.250 prog2[3503:303] oneONE

2013-11-14 20:43:20.250 prog2[3503:303] two

2013-11-14 20:43:20.250 prog2[3503:303] three

2013-11-14 20:43:20.251 prog2[3503:303] dataArray2:

2013-11-14 20:43:20.251 prog2[3503:303] oneONE

2013-11-14 20:43:20.251 prog2[3503:303] two

2013-11-14 20:43:20.251 prog2[3503:303] three