Function template return type deduction

Question

I have some class C with const and non-const getters for some generic type Node:

template 

        

Answer 1

You should write two alias functions, one for non-const instance and the other for const instance:

template 
const NodeType& AliasGetNode(const CType* cobject) const;  // for const instance. 
// The function must be const since the only difference between return type will cause redefinition error.

template 
NodeType& AliasGetNode(CType* cobject);  // for non-const instance

The instances declared const will call the const functions if there are overload functions. Of course, non-const instances will call the non-const version of the overload function. For example:

class Aclass {
    public:
       string test() { return "calling non-const function"; }
       string test() const { return "calling const function"; }
};

int main() {
    Aclass a;
    const Aclass b;

    cout << a.test() << endl;
    cout << b.test() << endl;

    return 0;
}

The result will be:

calling non-const function
calling const function