Thread: A question about 'Return Value'

I have the following code just for fun

Code:

class Base{
public:
	Base(){cout<<"Constructor"<<endl;}
	Base(const Base &obj){cout<<"Copy Constructor"<<endl;}
	Base & operator=(const Base& obj){
		cout<<"Operator="<<endl;
		return *this;
	}
};

Base foo(){
	Base x;
	return x;
}

void main(){
	Base tmp = foo();
}

=================
Why the outputs are only

Constructor
Copy Constructor

But I think the outputs should be:
Constructor
Copy Constructor // from return x
Copy Constructor // from Base tmp = foo();