[Resolved] Classes and Destructors

[The Hobo]

I've never officially learned about classes, I just use them all the time but never really understand them. So a few questions:

1) What is the purpose of the desctructor? Does it just clear up memory?

2) What's wrong with this?:

class square_info {
    private:
        float h, w;


    public:
        square_info () {
            h = 0;
            w = 0;
        }

        square_info (float height, float width) {
            h = height;
            w = width;
        }

        void print() {
            cout << "h: " << h << " | w: " << w << endl;
        }

        ~square_info(); //adding this line gives linking errors?
};

Thanks in advance.