c++ class member initialization order
ISO+IEC+14882-2011-C++11标准.pdf
12 Special member functions
12.6.2 Initializing bases and members
In a non-delegating constructor, initialization proceeds in the following order:
— First, and only for the constructor of the most derived class (1.8), virtual base classes are initialized in
the order they appear on a depth-first left-to-right traversal of the directed acyclic graph of base classes,
where “left-to-right” is the order of appearance of the base classes in the derived class base-specifier-list.
— Then, direct base classes are initialized in declaration order as they appear in the base-specifier-list
(regardless of the order of the mem-initializers).
— Then, non-static data members are initialized in the order they were declared in the class definition
(again regardless of the order of the mem-initializers).
— Finally, the compound-statement of the constructor body is executed.
[ Note: The declaration order is mandated to ensure that base and member subobjects are destroyed in the
reverse order of initialization. — end note ]
referrence:
