它是一个指针，因此请尝试：

It's a pointer, so instead try:

a->f();

基本上是运算符。（用于访问对象和引用使用对象的字段和方法），因此：

Basically the operator . (used to access an object's fields and methods) is used on objects and references, so:

A a;
a.f();
A& ref = a;
ref.f();

如果您使用的是指针类型，则必须先取消引用以获得引用：

If you have a pointer type, you have to dereference it first to obtain a reference:

A* ptr = new A();
(*ptr).f();
ptr->f();

a-&b; $ 表示法是通常只是（* a）.b 的简写。

The a->b notation is usually just a shorthand for (*a).b.

operator-> 可以重载，这在智能指针中尤为明显。当您正在使用智能指针时>，那么您还可以使用-> 来引用指向的对象：

The operator-> can be overloaded, which is notably used by smart pointers. When you're using smart pointers, then you also use -> to refer to the pointed object:

auto ptr = make_unique<A>();
ptr->f();