Define a Default Constructor
All
RWCollectable classes must have a default constructor. The default constructor takes no arguments. The persistence mechanism uses this constructor to create an empty object, then restore that object with appropriate contents.
Default constructors are necessary in order to create vectors of objects in C++, so providing a default constructor is a good habit to get into anyway. Here's a possible definition of a default constructor for our Bus class.
Bus::Bus() :
busNumber_ (0),
driver_ ("Unknown"),
passengers_ (rwnil)
{
}
