Generic Indexer - speed & safety issues

meetaligoel

Hello, I'm currently working on a simple genetic algorithm where I have implemented the chromosomes as a class working as an indexer. The class holds a private array of type object representing the genes. I've done that to keep flexible with regards to using different representations (int, float, bits etc.). Now, because of that, the genes can be assigned different types (e.g. Genes 1-3 = int, Genes 4 - 5 = strings.) This is nice, but not desirable (accidental assignments of the wrong type may happen). I also suspect that this flexibility costs speed as the program has to juggle around the different types as and when they are assigned to the individual genes. Is this the case, and is there a reason for concern? Would I be better of defining a template (does that work in c#?) or just setting up a class with lots of overloaded methods (for the individual types)? Many thanks, N.

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meetaligoel23y ago
Thanks ... I'm slowly coming to grips with the language. Please also see my new post regarding types & arrays. Regards, N.
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andrew23y ago
I don't think that generics would help you much, because your array would still have to be one type. Your approach is not inefficient, because when you cast from object to int or from int to object, you're boxing that int as an object. i.e. if you do object x = 3; then you're creating new object on the heap that will hold value 3, but it's going to be heap object not stack allocated. When you manipulate lots of those, then you'll have a lot of heap allocations. Unfortunatelly you can't have generic return type (even in generic c#, or most other languages) so no solution would work for you as indexer, except returning object and casting as you have it now. Internally you could store your values in different arrays, one for each type, but I don't think it's a nice solution, so maybe your approach thou unefficient, is the most elegant. To overcome some of the casting, you can have different methods for getting values: getInt(int index), getString(int index), that way at least your return values will be typesafe. And you can also do that for set, and inside of those methods just check if the index is good for given type.
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