Question

Assume the following dummy template:

template < class DataType > class Dummy
{
public:
    void init( )
    {
        m_data = DataType( 0 );
    }

private:
    DataType m_data;
};

Calling init will init the internal data. This does work fine when DataType is a standard data type (e.g. int or float). When DataType is a class this class must have a corresponding constructor.

Now assume DataType shall be e.g. a Complex Number represented by a suitable class. In this case it does not make sense to give the Complex number class a constructor with one argument because under normal conditions you want initialize real and imaginary part.

So my question is:
What is the best generic way to initialize a template type under consideration that the template shall be suitable to store any data type.

I think e.g. the STL must implement thinks like this but I am lost within that code.

Answer 1

In your example I guess you meant:

DataType( 0 );

Not:

Data ( 0 );

In any case, try:

m_data = DataType();

That will call the default constructor for a class type, or will zero-init for a built-in type.