C ++ class usage notes

C ++ class usage notes
When we create A class, we sometimes want to initialize the class members to 0; for example, class A; we define A m_a; sometimes we will simply use memmset (& m_a, 0, sizeof (A); in this way, it seems that the m_a member is cleared by 0. In fact, this usage is incorrect. In fact, when we create A class object, the class object has a function table. If 0 is cleared, all these tables will be invalid. In this case, the program's memory access error is often returned. So we can go to Struct to clear 0, but be careful with any memory operations of the class.