Create 18. Largest element

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

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+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
+
+
+
+
+