This quiz asks you to complete the two methods described below. Each item to be

Question

This quiz asks you to complete the two methods described below. Each item to be filled in is marked by ?n?. Question n asks you to fill in ?n?. The generic maxElement method returns the maximum element in a collection. If the collection has no elements, then this method should return null. The generic declaration needs to ensure that the compareTo method can be used. public static ?2? maxElement(Collection collection) { T max = null; for (?4? element: ?5?) { if (?6? == null || ?7?.compareTo(?8?) set = new TreeSet(); while (?14? (); for (int i: ?17?) { result.? 18?(list.? 19?(?20?)); } return result; }

Explanation / Answer

/**The method maxElement that takes a Collection class
   * and finds the maximum element in collection and returens
   * max value. The method maxElement extends Comparable interface
   * on T element
   * */
   public static <T extends Comparable<T>>
   T maxElement(Collection <? extends T> collection)
           {
       //Assum max element is starting element
       T max=collection.iterator().next();
       //Comparing th max with collection
       for( T element : collection)
       {
           if(element.compareTo(max)>0)
           {
               max=element;
           }
       }
       //return max value
       return max;
           }

---------------------------------------------------------------------------------------
//Test java program for maxElement

//Generic.java
import java.util.Collection;
import java.util.LinkedList;
public class Generic
{
   public static void main(String[] args)
   {
       // create link list object
       LinkedList<Integer> list = new LinkedList<Integer>();

       // populate the list
       list.add(18);
       list.add(42);
       list.add(45);
       list.add(15);
       list.add(32);
       System.out.println("LinkedList elements");
      
       for (Integer element : list) {
           System.out.println(element);
       }
      
       System.out.println("Maximum Element : ");
       //Calling generic function maxElement with list as argument
       System.out.println(maxElement(list));
      
   }

   /**The method maxElement that takes a Collection class
   * and finds the maximum element in collection and returens
   * max value. The method maxElement extends Comparable interface
   * on T element
   * */
   public static <T extends Comparable<T>>
   T maxElement(Collection <? extends T> collection)
           {
       //Assum max element is starting element
       T max=collection.iterator().next();
       //Comparing th max with collection
       for( T element : collection)
       {
           if(element.compareTo(max)>0)
           {
               max=element;
           }
       }
       //return max value
       return max;
           }
}
-----------------------------------------
Sample output:
LinkedList elements
18
42
45
15
32
Maximum Element :
45

--------------------------------------------------------------------------------------
/**
   * The method randomSubset that takes the List of type integer
   * values and takes a n value as input arguments.
   * The method that returns the random set of vlaues
   * */
   public static <T> List <? extends Number>
   randomSubset(List<Integer> list, int n)
           {
       //Create an instance of Random class
       Random random=new Random();
       //Create a Set object
       Set<Integer> set= new TreeSet<Integer>();
      
       //Add random values to set
       while(set.size()!=n)
       {
           set.add(random.nextInt(list.size()));
          
       }
      
       //Create a list of type Integer
       List<Integer>result=new ArrayList<Integer>();
      
       //Add list elements to the result from randomely
       //generated set
       for( int i : set)
       {
           result.add((Integer) list.get(i));
       }
       //return result
       return result;
   }

-------------------------------------------------------------------------------------------
//Sample test program for randomSubset

//Generic2.java
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Set;
import java.util.TreeSet;
public class Generic2
{
   public static void main(String[] args)
   {
       // create link list object
       List<Integer> list = new ArrayList<Integer>();

       // populate the list
       list.add(-18);
       list.add(40);
       list.add(-45);
       list.add(12);
       list.add(25);
       list.add(22);
      
       System.out.println("Random set : ");
       System.out.println(randomSubset(list,2));
      
      
      
   }

   /**
   * The method randomSubset that takes the List of type integer
   * values and takes a n value as input arguments.
   * The method that returns the random set of vlaues
   * */
   public static <T> List <? extends Number>
   randomSubset(List<Integer> list, int n)
           {
       //Create an instance of Random class
       Random random=new Random();
       //Create a Set object
       Set<Integer> set= new TreeSet<Integer>();
      
       //Add random values to set
       while(set.size()!=n)
       {
           set.add(random.nextInt(list.size()));
          
       }
      
       //Create a list of type Integer
       List<Integer>result=new ArrayList<Integer>();
      
       //Add list elements to the result from randomely
       //generated set
       for( int i : set)
       {
           result.add((Integer) list.get(i));
       }
       //return result
       return result;
   }
}

--------------------------------------------------------------------------------------------------------
Sample Output:
Random set :
[-45, 25]

Random set :
[-45, 22]

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.