class初始化中的指针初始化

Question

给出

class Foo {
    public:
        bool *b;
        Foo();
};
Foo::Foo()
    :b()
{      
}

int main()
{
    Foo foo;
}

b() 在 class 初始化列表中有什么作用？似乎可以将指针的值初始化为 0.

Answer 1

这是value initialization; as the effect, built-in types will be zero-initialized. That means b will be initialized to 0 (the null pointer).

4) otherwise, the object is zero-initialized.

和

If T is a scalar type, the object's initial value is the integral constant zero explicitly converted to T.

还有

Zero- and value-initialization also initialize pointers to their null values.

Pointer initialization in class initialization