Doubleton pattern in C ++

Question

I know a singleton pattern in C ++, but how do you get two instances of an object? Is there such a template where we could easily get two objects?

For the logic I could think of, I can modify the singleton pattern itself to create two objects inside it. This works, but if the requirement grows, as if I needed 3 or only 4 objects, which design pattern would fit this requirement?

Answer 1

There is a principle in software development that “there are only three digits: 0, 1 and infinity”, which means that arbitrary restrictions are bad. Sometimes there are good reasons to have only one of the resources (for example, a log file). As soon as you have more than one, any arbitrary limit will eventually become a problem. Therefore, if you need more than one resource or object, you will need a pool that can contain an arbitrary number. You also need to choose how to allocate resources from the pool.

Answer 2

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Answer 3

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myclass obj2;

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Answer 4

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Answer 5

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Answer 6

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Answer 7

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Answer 8

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Answer 9

If you need multiple instances of the same object, you can use the object pool.

If you need a map of many Singleton objects, you can use the Multiton template.