Does a constructor / destructor have to have code, or is the function enough?

Question

So if I have a class

class Transaction {

int no;
char dollar;

public:

    Transaction();
    ~Transaction();
}

And in my constructor / destr

Answer 1

Your class has only simple data members, so you don't even need (or should want) a destructor.

You should, however, initialize your data members in the constructor:

Transaction::Transaction()
  : no(0), dollar('$') {
    cout << "Entering constructor" << endl;
}

Otherwise, they will not be initialized, and may contain random values (C++ doesn't guarantee initialization of primitive non-static members to any particular value if you don't initialize them in the constructor). This can be particularly insidious if you have pointer members.