Usage of the “copy” property attribute to maintain an immutable NSString
问题 I am very new to iOS development and programming in Objective-C. I have been doing the exercises on the app dev library. This is the current exercise that I am trying to understand. 3. Test what happens if you set a mutable string as the person’s first name, then mutate that string before calling your modified sayHello method. Change the NSString property declarations by adding the copy attribute and test again. I attempt to do this however, the NSString that I modify does in fact change