Question

I’ve worked a fair amount with singleton classes in C++ (for a class), and now for a not-class project, I’m attempting to use inherited classes.

For some reason, I’m being really thick about constructor chains.

Consider the following:

class SuperClass
{
    string privateKey;
    string publicKey;
    string name;

public:
    enum Key {PUBLIC, PRIVATE};
    SuperClass(Key, string);
};

SuperClass::SuperClass(Key key, string theKey)
{
    switch(key)
    { 
        case PUBLIC: publicKey = theKey;
                     break;
        case PRIVATE: privateKey = theKey;
                     break;
    }
}


class SubClass : private SuperClass
{
public:
    SubClass(string key);
};

SubClass::SubClass(string key)
: SuperClass(SuperClass::PUBLIC, key) // "SubClass" will only interact with the public key, in this case.
{
    cout << "I'm instantiated!" << endl;
}

int main()
{
    SubClass example ("thisIsThePublicKey");
    return 0;
}

When compiling, I get the following error:

error: no matching function ncall to SuperClass::SuperClass()
note: candidates are: SuperClass::SuperClass(SuperClass::Key, std::string)

Why do I get this? Haven’t I used the constructor it says is a candidate?
I feel like I’ve read every tutorial on constructor chains, and I still don’t get what I’m supposed to be doing differently.

Thanks for any help!

Answer 1

I believe you forgot to inherit from your super class:

class SubClass

Should be:

class SubClass : public SuperClass