Week 2: Methods, strings and lists/18. Largest element

Write method

int largestElement(ArrayList<Integer> numberse)

which returns the largest of the elements in the integer list called numbers.


Example method call:
public static void main(String[] args) {
    ArrayList<Integer> testnumbers = new ArrayList<>();
    testnumbers.add(4);
    testnumbers.add(9);
    testnumbers.add(3);
    testnumbers.add(-2);

    int largest = largestElement(testnumbers);
    System.out.println("Largest: " + largest);
}

Program outputs:
Largest: 9







import java.util.Random;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.stream.Collectors;

public class Test{
    public static void main(String[] args){
        final Random r = new Random();
        
        test(new int[]{4,20,3,6,7,8,9,11,13,16,17});
        test(new int[]{1,5,2,4,3,6,4,7,5,8,6,3,9,5,3});
        test(new int[]{-5,-4,-1,-2,-3,-6,-7});
        
        int length = r.nextInt(10) + 10;
        int[] l = new int[length];
        for (int i=0; i<length; i++) {
            l[i] = (100 - r.nextInt(200));
        }
        test(l);
        
        
    }
    
    public static void test(int[] l) {
        ArrayList<Integer> list = new ArrayList<>();
        for (int a : l) {
            list.add(a);
        }
        System.out.println("Testing with list " + list);
        System.out.println("Largest element: " + largestElement(list));
        System.out.println("");
    }
    

    //ADD
    public static int largestElement(ArrayList<Integer> numbers) {
      int max=-999;
      for (int num: numbers) {
        if (num>max) {
          max = num;
        }
      }
      return max;
    }



}









Testing with list [4, 20, 3, 6, 7, 8, 9, 11, 13, 16, 17]
Largest element: 20

Testing with list [1, 5, 2, 4, 3, 6, 4, 7, 5, 8, 6, 3, 9, 5, 3]
Largest element: 9

Testing with list [-5, -4, -1, -2, -3, -6, -7]
Largest element: -1

Testing with list [-18, 1, 41, 73, 60, 89, 14, -70, -8, -75, -14, -35, 78, 35, 36]
Largest element: 89