Using a Super Class's Constructor

The class definition for Video has a constructor that initializes the member data of Video objects. The class Movie has a constructor that initializes the data of Movie objects. The constructor for class Movie looks like this:

// constructor
public Movie( String ttl, int lngth, String dir, String rtng )
{
  super(ttl, lngth);               // use the super class's constuctor
  director = dir;  rating = rtng;  // initialize the members new to Movie
}

The statement super(ttl, lngth) invokes a constructor of the parent to initialize some of the data. There are two constructors in the parent. The one that is invoked is the one that matches the argument list in super(ttl, lngth). Then the next two statements initialize the members that only Movie has.

Note: super() must be the first statement in the subclass's constructor.