C++虚函数指针

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https://www.cnblogs.com/raichen/p/5610679.html#:~:text=%E7%94%A8sizeof%E5%AF%B9,%E9%A2%9D%E5%A4%96%E5%A2%9E%E5%8A%A0%E7%9A%84%E5%AD%97%E8%8A%82%E3%80%82