Question

There are two classes defined..

    class Dictionary
    {
    public:
        Dictionary();
        Dictionary(int i);
// ...
    };

and

    class Equation
    {
        static Dictionary operator_list(1);
// ...

    };

but the problem is, whenever I compile this, I get a weird error message

error C2059: syntax error : ‘constant’

But it compiles well when I use the default constructor on operator_list.

Answer 1

In C++ you cannot combine declaration and initialization. When you do not specify constructor parameters of operator_list, you do not call its default constructor: you simply declare it. You need to also initialize it in the corresponding C++ file, like this:

Equation.h

class Equation {
    static Dictionary operator_list;
};

Equation.cpp:

Dictionary Equation::operator_list(1);

Note the absence of static in the CPP file: it is not there by design. The compiler already knows from the declaration that operator_list is static.

Edit: You have a choice with static constant members of integral and enumerated types: you can initialize them in the CPP file as in the example above, or you can give them a value in the header. You still need to define that member in your C++ file, but you must not give it a value at the definition time.