Overloading operator= for structs, within classes

Question

We have the following: (pseudoish)

class MyClass
{
    private:
       struct MyStruct{
          MyStruct operator=(const MyOtherStruct& rhs);
          int am1;
          int am2;
       };
};

We'd like to overload the = operator in the MyClass.cpp to do something like:

MyStruct&
MyStruct::operator=(const MyOtherStruct& rhs)
{
   am1 = rhs.am1;
   am2 = rhs.am2;
}

However, it doesn't want to compile. We're getting an error similar to

"missing ; before &"

and

"MyStruct must be a class or namespace if followed by ::"

Is there some concept here I'm missing?

Answer 1

You need to move your operator= for MyStruct into the struct declaration body:

class MyClass
{
    private:
       struct MyStruct{
          int am1;
          int am2;

          MyStruct& operator=(const MyOtherStruct& rhs)
          {
             am1 = rhs.am1;
             am2 = rhs.am2;
             return *this;
          }
       };
};

Or if that's not possible because MyOtherStruct is incomplete or don't want to clutter the class declaration:

class MyClass
{
    private:
       struct MyStruct{
          int am1;
          int am2;

          MyStruct& operator=(const MyOtherStruct& rhs);
       };
};

inline MyClass::MyStruct& MyClass::MyStruct::operator=(const MyOtherStruct& rhs)
{
    am1 = rhs.am1;
    am2 = rhs.am2;
    return *this;
}