©TCP-tryJAVA

import java.util.Optional;
import java.util.stream.*;

public class prog {
	public static void main(String[] args){
		Stream<String> stream1 = Stream.of("넷", "둘", "셋", "하나");
		Stream<String> stream2 = Stream.of("넷", "둘", "셋", "하나");
		
		Optional<String> result1 = stream1.reduce((s1, s2) -> s1 + "++" + s2);
		result1.ifPresent(System.out::println);
		
		String result2 = stream2.reduce("시작", (s1, s2) -> s1 + "++" + s2);
		System.out.println(result2);
	}
}