import java.util.Arrays; import java.util.List; import java.util.stream.Stream; public class CostAlloc { public static void main(String[] args) { List<Double> costs = Arrays.asList(1.0, 2.0, 3.0, 4.0); Stream<Double> streaml = costs.stream(); // costsを合計する Double suml = streaml .reduce((t,u) -> t + u) .get(); System.out.println(suml); System.out.println(""); // costsの全ての要素をcostsの合計で割る costs.forEach(cost -> System.out.println(cost / suml)); } }