Could you provide me the reason to why the key type for CCObject in CCDictionary has been deleted?

I was aware that CCObeject is similar to NSObject, but CCDictionary does not use the key type for CCObject.

Your explanation would be very helpful. Thank you in advance for your help.

Coz in most scenarios, the key-value pair is int-CCObject. It’s enough for the engine interfaces. Reducing the usage of c*+ templates can make it more friendly to c*+ beginners.
If you gonna to organize your logic data, you can consider std::map.