Method main

Lecture 24 - Arraylist/src/Main.java:4–63

(String[] args)

public class Main {
    public static void main(String[] args) {
        //wrapper classes
//        Integer in = Integer.valueOf(4);
//        System.out.println(in);
//        Float f = Float.valueOf(4.5f);
//        System.out.println(f);

        ArrayList<Integer> l1 = new ArrayList<>();

        // add new element

        l1.add(5); // 5
        l1.add(6); // 5 6
        l1.add(7); // 5 6 7
        l1.add(8); // 5 6 7 8

        // get an element at index i
//        System.out.println(l1.get(1)); // 6


//        // print with for loop
//        for(int i = 0; i < l1.size(); i++){
//            System.out.println(l1.get(i)); // 5, 6, 7, 8
//        }

        //printing the array list directly
        System.out.println(l1); // [5, 6, 7, 8]

        //adding element at some index i
        l1.add(1, 100);
        System.out.println(l1); // [5 100 6 7 8]


        //modifying element at index i
        l1.set(1, 10);
        System.out.println(l1); // [5, 10, 6, 7, 8]


        //removing an element at index i
        l1.remove(1);
        System.out.println(l1); // 5, 6, 7, 8


        //removing an element e
        l1.remove(Integer.valueOf(7));
        System.out.println(l1); // 5, 6, 8

        //checking if an element exists
        boolean ans = l1.contains(Integer.valueOf(60));
        System.out.println(ans);

        // if you don't specify class, you can put anything inside l
        ArrayList l = new ArrayList();
        l.add("pqres");
        l.add(1);
        l.add(true);
        System.out.println(l);