above/below average

package ch.fhnw.claudemartin;

import java.util.*;
import java.util.concurrent.atomic.LongAdder;

public class SomeClass {
  public static void main(final String[] args) {
    final double[] data = { -12.7, -8.3, 2, 2.4, 3.5, 5.8, 21.3 };

    final DoubleSummaryStatistics stats = Arrays.stream(data)
        .summaryStatistics();
    final double avg = stats.getAverage();
    final long count = stats.getCount();
    System.out.println("average: " + avg);

    final Map<String, LongAdder> map = new TreeMap<>();
    final LongAdder below = map.compute("below", (k, v) -> new LongAdder());
    final LongAdder above = map.compute("above", (k, v) -> new LongAdder());
    final LongAdder equal = map.compute("equal", (k, v) -> new LongAdder());

    Arrays.stream(data).forEach(d -> (d > avg ? above : d < avg ? below : equal).increment());

    map.entrySet().stream().forEach(e -> System.out.format("%s: %f %%%n",
        e.getKey(), 100D * e.getValue().longValue() / count));
  }
}