brace-or-equal-initializers 初始化顺序
brace-or-equal-initializers initialization order
如果使用brace-or-equal-initializers，成员变量的初始化顺序是什么？它们的初始化与代码顺序相同吗？
struct foo {
int x = 1;
int y = x + 1;
} bar;
无论编译器如何，bar.y 总是 2 吗？
是的，y保证在x之后初始化。非静态数据成员总是 initialized in order of their declaration in the class definition, regardless of how they're initialized (by member initializer list or default member initializer, even default initialization).
3) Then, non-static data member are initialized in order of
declaration in the class definition.
来自 Scott Meyers 的书，Effective C++，第 4 项：
One aspect of C++ that isn’t fickle is the order in which an object’s
data is initialized. This order is always the same: base classes are
initialized before derived classes (see also Item 12), and within a
class, data members are initialized in the order in which they are
declared.
如果使用brace-or-equal-initializers，成员变量的初始化顺序是什么？它们的初始化与代码顺序相同吗？
struct foo {
int x = 1;
int y = x + 1;
} bar;
无论编译器如何，bar.y 总是 2 吗？
是的，y保证在x之后初始化。非静态数据成员总是 initialized in order of their declaration in the class definition, regardless of how they're initialized (by member initializer list or default member initializer, even default initialization).
3) Then, non-static data member are initialized in order of declaration in the class definition.
来自 Scott Meyers 的书，Effective C++，第 4 项：
One aspect of C++ that isn’t fickle is the order in which an object’s data is initialized. This order is always the same: base classes are initialized before derived classes (see also Item 12), and within a class, data members are initialized in the order in which they are declared.