const vs. non-const for member functions

const objects can only call const functions

Let's have a look!

As you can see,the object is decorated by const,so it can not call the getName() member function.

But if we decorate the function using const after it,which means that it becomes a const member function.

Since then,it can not change the object's attribute,because it is a const member function.

Rember: Placing const after the function's parameter list indicates that the function is a const member function.This means that the function won't modify any non-mutable members of the class. It's a promise that the function won't change the state of the object it's called on.

So,what's the meaning of const before the function.

Placing const before the function's return type indicates that the returned value is a constant value. It means that the function returns a const value, and this value cannot be modified.

So,what is mutable ,just see the article in my blog...