Nội dung kiến thức:
- Enum trong java
- Khai báo mảng trong java
- Khai báo mảng động trong java

#Main.java

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package lesson02;

import java.util.ArrayList;
import java.util.Scanner;

/**
 *
 * @author Diep.Tran
 */
public class Main {

    public static void main(String[] args) {
//        testEnum();
//        testArray();
        testDynamicArray();
    }

    public static void testDynamicArray() {
        //Khai bao mang dong
        ArrayList<Integer> t = new ArrayList<>();
//        ArrayList<Float> f = new ArrayList<>();
//        ArrayList<String> s = new ArrayList<>();
        
        //Them 1 phan vao trong mang
        t.add(12); //index = 0
        t.add(7); // index = 1
        t.add(90); // index = 2
        
        System.out.println("length: " + t.size());
        System.out.println("index = 2: " + t.get(2));
        
        //Xoa 1 phan tu khoi mang
        t.remove(1);
        System.out.println("index = 1: " + t.get(1));
        
        Scanner scan = new Scanner(System.in);
        System.out.println("x = ");
        int x = scan.nextInt();
        t.add(x);
        
        //Lay du lieu trong mang ra
        for (int i = 0; i < t.size(); i++) {
            System.out.printf("\nt[%d] = %d", i, t.get(i));
        }
    }

    public static void testArray() {
        Scanner scan = new Scanner(System.in);

        //Khai bao mang so nguyen gom 5 phan tu.
        int[] t = new int[5];
        //Chu y: Thay kieu du lieu khac -> thay int -> String, char, float, double, ...
        //Gan du lieu
        t[0] = 6;
        t[1] = 9;
        System.out.println("Nhap t[2] = ");
        t[2] = scan.nextInt();

        //Nhap cho ca mang
        for (int i = 0; i < t.length; i++) {
            System.out.printf("\nNhap t[%d] = ", i);
            t[i] = scan.nextInt();
        }
        //Tinh tong cac so chan trong mang t
    }

    static enum LIGHT_STATUS {
        ON, OFF
    };

    static enum STUDENT_STATUS {
        PENDING, APPROVED, LEARNING, DROPOUT
    };

    public static void testEnum() {
        //Xay dung 1 chuong trinh quan ly trang thai bong den.
        //status: ON - OFF
        //Cach 1:
        //String status = "ON";//"OFF"
        //Cach 2:
        /**
         * status: 0 -> OFF status: 1 -> ON
         */
        //int status = 0;
        LIGHT_STATUS status = LIGHT_STATUS.ON;
        System.out.println("status: " + status);

        //Quan ly trang thai hoc cua sinh vien: PENDING, APPROVED, LEARNING, DROPOUT, ...
        /**
         * 0 -> PENDING 1 -> APPROVED 2 -> LEARNING 3 -> DROPOUT 4 -> ...
         */
        STUDENT_STATUS status1 = STUDENT_STATUS.LEARNING;

        switch (status) {
            case ON:

                break;
            case OFF:

                break;
        }
    }
}