Dealing with User-Defined Types and Read-Only Functions

[Daleth]

User Defined Types:

When a friend function returns an instance, what is the difference between the following operator functions?

//Operator+ 1 without constructor
MyClass operator+(const MyClass& ThisClass, const MyClass& ThatClass){
      return ThisClass.number + ThatClass.number;
}
//Operator+ 2 using class constructor
MyClass operator+(const MyClass& ThisClass, const MyClass& ThatClass){
      return MyClass(ThisClass.number + ThatClass.number);
}

Read-Only functions:

And... What is the difference between these two functions?

void MyClass::foo(const MyClass& ThisClass, const MyClass& ThatClass){
//Do something...
}
void MyClass::foo(MyClass& ThisClass, MyClass& ThatClass) const {
//Do same something
}

[vlad from moscow]

When you post some code then test it yourself that it at least is compiled.
This statement will not b compiled

friend MyClass operator+(const MyClass& ThisClass, const MyClass& ThatClass) const;

because functions that are not members of classes may not have the qualifier const

[Daleth]

Oop, sorry. That part you pointed out was a typo.

But when I tried compiling the operator+ functions, they both returned the same instance when given the same parameters. I was hoping to learn if there was any risk in using one method over another.

[vlad from moscow]

The const qalifier of non-static member functions means that access to class members is done using const this Thus these functions can not change objects that call these functions.

[Daleth]

So, they are essentially the same?

[vlad from moscow]

I have not understood why did you make this resume. I pointed out already the difference.