feat: kata/average-of-even-numbers-in-a-list

Author: ParanoidUser

kata/beta/average-of-even-numbers-in-a-list/README.md

@@ -1,35 +1,41 @@
 # [Average of Even Numbers in a List](https://www.codewars.com/kata/average-of-even-numbers-in-a-list "https://www.codewars.com/kata/685a10c62388b0a0220ac88d")
 
-# Average of Even Numbers in a List
-
 Your task is to write a method that calculates the average of all even numbers in a list of integers.
 If the list contains no even numbers, return `0.0`.
 
 ---
 
 ## Function Signature
+
 ```java
 public static double averageOfEvens(List<Integer> numbers)
 ```
 
 ---
 
 ## Input
+
 A `List<Integer>` of length n (1 ≤ n ≤ 100,000)
 
 ---
 
 ## Output
-A `double` representing the average of all even numbers in the list. 
+
+A `double` representing the average of all even numbers in the list.
 If there are no even numbers, return `0.0`
 
 ---
 
 ## Examples
+
 ```java
-averageOfEvens(Arrays.asList(2, 4, 6, 8, 10)) => 6.0
-averageOfEvens(Arrays.asList(1, 3, 5)) => 0.0
-averageOfEvens(Arrays.asList(10, 15, 20, 25, 30)) => 20.0
-averageOfEvens(Arrays.asList(0, 0, 0)) => 0.0
-averageOfEvens(Arrays.asList(1, -4, -6, 3)) => -5.0
-```
+averageOfEvens(Arrays.asList(2, 4,6,8,10))=>6.0
+
+averageOfEvens(Arrays.asList(1, 3,5))=>0.0
+
+averageOfEvens(Arrays.asList(10, 15,20,25,30))=>20.0
+
+averageOfEvens(Arrays.asList(0, 0,0))=>0.0
+
+averageOfEvens(Arrays.asList(1, -4,-6,3))=>-5.0
+```

kata/beta/average-of-even-numbers-in-a-list/main/EvenAverage.java

@@ -0,0 +1,7 @@
+import java.util.List;
+
+interface EvenAverage {
+  static double averageOfEvens(List<Integer> numbers) {
+    return numbers.stream().mapToInt(i -> i).filter(i -> i % 2 == 0).average().orElse(0);
+  }
+}

kata/beta/average-of-even-numbers-in-a-list/test/SolutionTest.java

@@ -0,0 +1,15 @@
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+import org.junit.jupiter.api.Test;
+
+class SolutionTest {
+  @Test
+  void sample() {
+    assertEquals(6.0, EvenAverage.averageOfEvens(List.of(2, 4, 6, 8, 10)));
+    assertEquals(0.0, EvenAverage.averageOfEvens(List.of(1, 3, 5)));
+    assertEquals(20.0, EvenAverage.averageOfEvens(List.of(10, 15, 20, 25, 30)));
+    assertEquals(0.0, EvenAverage.averageOfEvens(List.of(0, 0, 0)));
+    assertEquals(-5.0, EvenAverage.averageOfEvens(List.of(1, -4, -6, 3)));
+  }
+}