package Progress; import java.util.Collection; /** * A student object that contains the name of the student and other information. */ public abstract class Student { private String name; private Collection enrolledClasses; /** * Adds a class to the student's list of enrolled classes. * @param cl class to be added *
     pre:
       // Class cl must not be null.
       cl != null;
   
     post:
       // The Class cl is now in this.enrolledClasses.
       enrolledClasses'.contains(cl); 
    *
    */
   public abstract void addClass(Class cl);
}