AP Computer Science --- Haas --- SelectionSortArrayList

/**
 * US States have name, population, and land area instance variables
 * 
 *    <<< This code is NOT complete >>>
 *    
 *    You must complete the compareTo method.
 */
public class State implements Comparable {
  private String name;
  private int population;
  private int landArea; // in square miles
  
  public State(String name, int landArea, int population)  {
      this.name = name;
      this.landArea = landArea;
      this.population = population;
    }

  public String getName() { 
      return name; 
  }

  public int getPopulation() {
      return population;  
  }

  public int getLandArea() { 
      return landArea;  
  }
  
  public String toString() {
      String blanks = "               ";
      return (name + blanks.substring(name.length()) +       
             " People Per Square Mile: " + population/landArea);
  }
  
  /**
   * <<< COMPLETE THE CODE: write a compareTo method >>>
   * Compares two states by population density.
   * (Population density is the number of people per land area.)
   * 
   *     1) returns value < 0 if "this" is less than "other"
   *     2) returns value = 0 if "this" is equal to "other"
   *     3) returns value > 0 if "this" is greater that "other" 
   */
  public int compareTo(Object other) {
      
      //<<< COMPLETE THE CODE >>>
   
  }    
}

/**
 * <<< This code is NOT complete. >>>
 * 
 * This class has a method "sort" which should perform 
 * a selection sort on an ArrayList of States.
 */
import java.util.*;
public class SelectionSortArrayList {

    /**
     * performs a selection sort on an ArrayList of States
     */
    public static void sort(ArrayList < State > aList) {
        
        // <<<< complete the code >>>>
        
       
    }
}

/**
 *     <<<  This code IS complete. >>>
 *     
 *  1) An ArrayList of US States is created.  
 *  2) Each state has a name, population, and land area.
 *  3) The states are sorted by population density.
 * 
 */
import java.util.*;
public class Tester
{
   public static void main(String args[])
   {
      ArrayList< State > myList = new ArrayList < State >();
      myList.add(new State("Alabama"    ,   50750   ,   4447100));
      myList.add(new State("Alaska"     ,   570374  ,   626932));
      myList.add(new State("Arizona"    ,   113642  ,   5130632));
      myList.add(new State("Arkansas"   ,   52075   ,   2673400));
      myList.add(new State("California" ,   155973  ,   33871648));
      myList.add(new State("Colorado"   ,   103729  ,   4301261));
      myList.add(new State("Connecticut",   4845    ,   3405565));
      myList.add(new State("Delaware"   ,   1955    ,   783600));
      myList.add(new State("Florida"    ,   53937   ,   15982378));
      myList.add(new State("Georgia"    ,   57919   ,   8186453));
      myList.add(new State("Hawaii"     ,   6423    ,   1211537));
      myList.add(new State("Idaho"      ,   82751   ,   1293953));
      myList.add(new State("Illinois"   ,   55593   ,   12419293));
      myList.add(new State("Indiana"    ,   35870   ,   6080485));
      myList.add(new State("Iowa"       ,   55875   ,   2926324));
      myList.add(new State("Kansas"     ,   81823   ,   2688418));
      myList.add(new State("Kentucky"   ,   39732   ,   4041769));
      myList.add(new State("Louisiana"  ,   43566   ,   4468976));
      myList.add(new State("Maine"      ,   30865   ,   1274923));
      myList.add(new State("Maryland"   ,   9775    ,   5296486));
      myList.add(new State("Massachusetts", 7838    ,   6349097));
      myList.add(new State("Michigan"   ,   56809   ,   9938444));
      myList.add(new State("Minnesota"  ,   79617   ,   4919479));
      myList.add(new State("Mississippi",   46914   ,   2844658));
      myList.add(new State("Missouri"   ,   68898   ,   5595211));
      myList.add(new State("Montana"    ,   145556  ,   902195));
      myList.add(new State("Nebraska"   ,   76878   ,   1711263));
      myList.add(new State("Nevada"     ,   109806  ,   1998257));
      myList.add(new State("New Hampshire", 8969    ,   1235786));
      myList.add(new State("New Jersey" ,   7419    ,   8414350));
      myList.add(new State("New Mexico" ,   121364  ,   1819046));
      myList.add(new State("New York"   ,   47224   ,   18976457));
      myList.add(new State("North Carolina",48718   ,   8049313));
      myList.add(new State("North Dakota"  ,68994   ,   642200));
      myList.add(new State("Ohio"       ,   40953   ,   11353140));
      myList.add(new State("Oklahoma"   ,   68679   ,   3450654));
      myList.add(new State("Oregon"     ,   96002   ,   3421399));
      myList.add(new State("Pennsylvania",  44820   ,   12281054));
      myList.add(new State("Rhode Island",  1045    ,   1048319));
      myList.add(new State("South Carolina",30111   ,   4012012));
      myList.add(new State("South Dakota",  75896   ,   754844));
      myList.add(new State("Tennessee"  ,   41219   ,   5689283));
      myList.add(new State("Texas"      ,   261914  ,   20851820));
      myList.add(new State("Utah"       ,   82168   ,   2233169));
      myList.add(new State("Vermont"    ,   9249    ,   608827));
      myList.add(new State("Virginia"   ,   39598   ,   7078515));
      myList.add(new State("Washington" ,   66581   ,   5894121));
      myList.add(new State("West Virginia", 24087   ,   1808344));
      myList.add(new State("Wisconsin"  ,   54314   ,   5363675));
      myList.add(new State("Wyoming"    ,   97105   ,   493782));
      
      // print out states UNSORTED
      System.out.println(" --------------- U - N - S - O - R - T - E - D ---------------");
      for (State i : myList) { System.out.println(i);  }
      
      // sort states by population density
      SelectionSortArrayList.sort(myList);
      
      // print out states SORTED by population density
      System.out.println(" \n --------------- S - O - R - T - E - D ---------------");
      for (Comparable i : myList) { System.out.println(i);  }
    }     
}