What are primitive types default-initialized to in C++?

Question

When I use an initialization list:

struct Struct {
    Struct() : memberVariable() {}
    int memberVariable;
};

the primitive type (

Answer 1

For primitive types, default initialisation means that the object is initialised with 0, 0.0 or NULL as appropriate for the type.

Edit: The above is valid for C++98. In C++03, the terms got redefined a bit. Now, using an initialiser of () (which is syntactically only possible for member-objects) results in value initialisation, which for primitive types means that the appropriate value of 0, 0.0 or NULL gets stored.