import java.util.*;

public class Main {
	public static void main(String[] args) {
		List<Integer> dataList;
		dataList = new ArrayList<>(); // can change, e.g., to: .. = new Vector<>();

		dataList.add(100);
		dataList.add(200);
		
		System.out.println(dataList);
	}
}

/*
print_data(dataList);

private static void print_data(List<Integer> dataList) {
	for (int i=0; i<dataList.size(); i++) {
		System.out.printf("%d: %d  ", i+1, dataList.get(i));
	}
}

private static void print_data(List<Integer> dataList) {
	int seq=1;
	
	Iterator<Integer> itr = dataList.iterator(); // like a Scanner
	while (itr.hasNext()) {
		System.out.print((seq++)+": "+itr.next()+"  ");
	}
}
*/

/*
import java.util.*;

public class Main {
	public static void main(String[] args) {
		List<Integer> dataList;
		dataList = new ArrayList<>();

		System.out.println("(a) Add a lot");
		createData1(dataList, 100000000); 
		// good numbers: 10000000 for LinkedList
		// good numbers: 100000000 for ArrayList

		System.out.println("(b) Insert at the beginning");
		createData2(dataList, 30); 
		// good numbers: 10000000 for LinkedList
		// good numbers: 30 for ArrayList

		System.out.println("done");
	}

	private static void createData1(List<Integer> dataList, int count) {
		for (int i = 0; i < count; i++) {
			dataList.add(i);
		}
	}

	private static void createData2(List<Integer> dataList, int count) {
		for (int i = 0; i < count; i++) {
			dataList.add(0, count); // insert at the beginning
		}
	}
}

		//// very fast even for linked list
		// System.out.println("(c) Read middle"); 
		// readMiddle(dataList);	

	//// very fast even for linked list
	// private static void readMiddle(List<Integer> dataList) {
	// 	int iMiddle = dataList.size()-1;
	// 	System.out.println(dataList.get(iMiddle));
	// }

 */