抽象函數和虛函數有什麼區別？ - What is the difference between an abstract function and a virtual function?

問題：

What is the difference between an abstract function and a virtual function? 抽象函數和虛函數有什麼區別？ In which cases is it recommended to use virtual or abstract? 建議在哪一種狀況下使用虛擬或抽象？ Which one is the best approach? 哪一種方法最好？

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解決方案：

參考一： https://stackoom.com/question/1dqF/抽象函數和虛函數有什麼區別
參考二： https://oldbug.net/q/1dqF/What-is-the-difference-between-an-abstract-function-and-a-virtual-function