Question

I have a class containing two properties:

public class player{
    public player(String playerName,int points){
        this.playerName=playerName;
        this.points=points;
    }
    public String getPlayerName() {
        return playerName;
    }
    public void setPlayerName(String playerName) {
        this.playerName = playerName;
    }
    public int getPoints() {
        return points;
    }
    public void setPoints(int points) {
        this.points = points;
    }
    private String playerName;
    private int points;
}

I have arrayList class contains collection of palyer objects.

List palyers=new ArrayList();
players.add(new player("mike",2));
players.add(new player("steve",3));
players.add(new player("jhon",7));
players.add(new player("harry",5);

Here my question is how to display player names with smallest points difference.

Output:

Based on the example code i written:

Mike and steve is the output

THis way comparison should happen:

mike to steve --> 1

mike to jhon--->5

mike to harry-->3

steve to mike -->1
steve to jhon--->5
steve to harry--->3

jhon to mike-->5
jhon to steve-->4
jhon to harry--->2

harry to mike -->3

harry to steve-->2

harry to jhon -->2

Based on above comparison mike and steve should display

Any java API to compare the properties?

Answer 1

So you want to know the pair of players whose score has the smallest difference?
I don’t think there’s an API function for that, although there might be something in the Apache Commons Collections.

Otherwise you’ll have to use a nested loop.

int res1 = -1, res2 = -1;

int maxDiff = Integer.MAX_VALUE;
for ( int i = 0; i < players.size( ); i++ )
{
    for ( int j = i + 1; j < players.size() ; j++ )
    {
        int diff = Math.abs( players.get(i).getPoints( ) - players.get(j).getPoints( ) );
        if ( diff < maxDiff )
        {
            maxDiff = diff;
            res1 = i;
            res2 = j;
        }           
    }
}
System.out.println(players.get(res1).getPlayerName( ) + " and " + players.get(res2).getPlayerName( ));

Obviously, this code needs some work; for example, if two pairs of players have the same difference between them, only the latest pair processed will be reported. You may also want to re-work this piece of code to remove the default values (Note how the System.out.println will crash if your List contains 0 players, for example). I leave these for you to solve. HTH.