/**
 * The purpose of this file is to illustrate some additional concepts 
 * about objects and classes.  This is not a correct commenting style 
 * and should not be duplicated in any real programs you write.
 * 
 * Concepts
 * 1) What is a "calling object" ?
 * 2) How do you pass in a parameter of the class type?
 * 3) How do you return a value of the class type?
 */
class WeightTester
{
    public static void main ( String args[] )
    {
        // Here we are ONLY declaring the variables w1 and w2.
        // No constructor will be called yet because no object
        // has been created yet.
        Weight w1;
        Weight w2;

        // Notice here we are creating two new objects of the
        // Weight class.  The constructor will be called for
        // each object.
        w1 = new Weight(5,3);
        w2 = new Weight(2,10);
        
        // Now we are invoking the print method for each object.  
        // In the first call, w1 is the variable of type Weight
        // that is making a call to the method "print" which is
        // part of the Weight class.  Thus w1 is the "calling 
        // object" -- meaning it is the object calling the
        // method print.  Ditto for w2 in the second statement.
        w1.print();
        w2.print();
        
        // Note about the above statements.  Here we call a method
        // print which prints the weights to the screen.  It would
        // be a far better design to use a toString method instead.
        // The only reason I do it this way here is so that I don't
        // give away the code for the homework assignment in #10.
        
        /*
         * Here again is an example of invoking a method which is
         * part of the class.  w1 is the calling object which is
         * calling the "add" method.  We have two new twists.  First
         * note that w2 is included as well.  This is a PARAMETER
         * which is also sent to the add method.  Look at the code
         * for the add method to see how we access both w1 and w2 
         * inside the method.  The other twist, a return type of
         * Weight is given as well.  We must create a new variable
         * of type Weight inside the method (3 different objects).
         * We will fill in the appropriate pounds and ounces and
         * return it from the add method so that we can assign
         * it to variable w3 in this program.
         */ 
        Weight w3 = w1.add(w2);
        w3.print();
    }
}