Manipulate_List

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class List_Operations {

    public static void main(String[] args) throws IOException {

        BufferedReader reader =
                new BufferedReader(
                        new InputStreamReader(System.in));

        System.out.println("Enter some numbers ");

        List<String> elements = Arrays.stream(reader.readLine().split("\\s+"))
                .collect(Collectors.toList());

        System.out.println("Enter command ");
        String input = " ";

        while (!"end".equalsIgnoreCase(input = reader.readLine())) {

            String[] data = input.split("\\s+");

            String command = data[0];

            switch (command) {
                case "Add":
                    elements.add(data[1]);

                    break;

                case "Insert":
                    String number = data[1];
                    int index = Integer.parseInt(data[2]);
                    if (0 <= index && index < elements.size()) {
                        elements.add(index, number);

                    } else {
                        System.out.println("Invalid index");
                    }

                    break;

                case "Remove":
                    index = Integer.parseInt(data[1]);
                    if (0 <= index && index < elements.size()) {
                        elements.remove(index);

                    } else {
                        System.out.println("Invalid index");
                    }

                    break;

                case "Shift":
                    int count = Integer.parseInt(data[2]);
                    if (data[1].equals("left")) {

                        for (int i = 0; i < count % elements.size(); i++) {
                            elements.add(elements.get(0));
                            elements.remove(0);
                        }

                    } else {
                        for (int i = 0; i < count % elements.size(); i++) {
                           elements.add(0, elements.get(elements.size() - 1));
                           elements.remove(elements.size() -1);

                        }

                    }

                    break;
            }

        }
        System.out.println(elements.toString().replaceAll("[\\[,\\]]", " "));
    }
}