Initial commit 7.2

src/main/java/_7/_2/StreamTest.java

@@ -0,0 +1,29 @@
+package _7._2;
+
+import java.util.stream.Stream;
+
+public class StreamTest {
+    public static void main(String[] args) {
+        Stream<Integer> naturals = Stream.iterate(1, i -> i + 1);
+
+        Stream<Integer> integers = Stream.iterate(0, i -> {
+            int next;
+            if (i>0) {
+                next = i*(-1);
+            } else {
+                next = i*(-1)+1;
+            }
+            return next;
+        });
+
+        System.out.println(filterAndSum(naturals));
+        System.out.println(filterAndSum(integers));
+    }
+
+    private static Integer filterAndSum(Stream<Integer> stream) {
+        return stream.filter((i) -> i % 2 == 0)
+                .limit(10)
+                .reduce((a,b) -> a+b)
+                .orElse(0);
+    }
+}