Object-Oriented Programming with Java, part I – Exercise 66

This program takes an array of numbers and then returns the largest number.

My Code

import java.util.ArrayList;
import java.util.Collections;

public class TheGreatest {
    public static int greatest(ArrayList<Integer> list) {
        // write code here
        Collections.sort(list, Collections.reverseOrder());
        return list.get(0);
    }

    public static void main(String[] args) {
        ArrayList<Integer> lista = new ArrayList<Integer>();
        lista.add(3);
        lista.add(2);
        lista.add(7);
        lista.add(2);
        
        System.out.println("The greatest number is: " + greatest(lista));
    }
}

Model Code

import java.util.ArrayList;

 

public class TheGreatest {

    public static int greatest(ArrayList<Integer> list) {

        // write code here

        // The first candidate for the greatest is the first in the list

        int greatestSoFar = list.get(0);

        // then we iterate over the whole list

        for (int luku : list) {

            // if a greater found, we take that as the candidate for greatest

            if (luku > greatestSoFar) {

                greatestSoFar = luku;

            }

        }

        return greatestSoFar;

    }

 

    public static void main(String[] args) {

        ArrayList<Integer> lista = new ArrayList<Integer>();

        lista.add(3);

        lista.add(2);

        lista.add(7);

        lista.add(2);

        

        System.out.println("The greatest number is: " + greatest(lista));

    }

}

Comments

I am quite happy with that. I didn’t want to go down the path of having to iterate the entire list so I just sorted it in reverse order and then returned list(0).