class A{ }; constexpr size_t sizeOfT = sizeof(A);
鼠标移动到sizeofT上可以看到A的大小
from:
https://stackoverflow.com/questions/24775127/how-to-find-the-size-of-a-structure-during-programming-in-visual-studio
ms vc++ 编码期计算对象大小
原文：https://www.cnblogs.com/wolbo/p/14873843.html
