BAEL-1586 Modified logic to use forEach loop (#3879)

* BAEL-1586 Modified logic to use forEach loop

* BAEL-1586 Added Unit Test For Finding Average Given an Empty Array

core-java/src/main/java/com/baeldung/array/SumAndAverageInArray.java

@@ -6,8 +6,8 @@ public class SumAndAverageInArray {
 
     public static int findSumWithoutUsingStream(int[] array) {
         int sum = 0;
-        for (int index = 0; index < array.length; index++) {
+        for (int value : array) {
-            sum += array[index];
+            sum += value;
         }
         return sum;
     }
@@ -22,6 +22,6 @@ public class SumAndAverageInArray {
     }
 
     public static double findAverageUsingStream(int[] array) {
-        return Arrays.stream(array).average().getAsDouble();
+        return Arrays.stream(array).average().orElse(Double.NaN);
     }
 }

core-java/src/test/java/com/baeldung/array/SumAndAverageInArrayTest.java

@@ -38,4 +38,13 @@ public class SumAndAverageInArrayTest {
 
         Assert.assertEquals(expectedAvgOfArray, actualAvgOfArray, 0.0034);
     }
+
+    @Test
+    public void givenAnEmptyIntArray_whenUsingStream_thenFindAverage() {
+        int[] array = {};
+        double expectedAvgOfArray = Double.NaN;
+        double actualAvgOfArray = SumAndAverageInArray.findAverageUsingStream(array);
+
+        Assert.assertEquals(expectedAvgOfArray, actualAvgOfArray, 0.00);
+    }
 }