#Test.java

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package aptech.lesson02;

import java.util.ArrayList;

/**
 *
 * @author Diep.Tran
 */
public class Test {
    public static void main(String[] args) {
        //Khai bao mang 5 so nguyen
        int[] t = new int[5];
        //length: 5, index: 0 -> 4
        t[0] = 5;
        t[1] = 6;
        
        System.out.println("t[0] = " + t[0]);
        
        //Khai bao mang gom cac so nguyen
        int[] k = {1, 5, 2, 5, 3};
        
        //duy qua cac phan tu trong mang
        for (int i = 0; i < 5; i++) {
            System.out.format("\nk[%d] = %d", i, k[i]);
//            System.out.println("k[" + i + "] = " + k[i]);
//            String str = "k[".concat(i+"").concat("] = ").concat(""+k[i]);
//            System.out.println(str);
        }
        System.out.println("");
        
        String[] sList = new String[3];
        sList[0] = "Sinh vien A";
        sList[1] = "ABC";
        
        //Khai bao mang dong -> dynamic.
        ArrayList<Integer> list = new ArrayList<>();//Tao ra 1 mang dong
        //Them 1 phan tu vao mang
        list.add(12);//length = 1 => list.size() => index = 0
        list.add(55);//length = 2 => list.size() => index = 1
        
        list.add(1, 100);
//        list.clear();
        
        for (int i = 0; i < list.size(); i++) {
            System.out.println("Phan tu >> " + list.get(i));
        }
        
        //Xoa 1 phan tu di
        list.remove(0);
        
        for (int i = 0; i < list.size(); i++) {
            System.out.println("Phan tu >> " + list.get(i));
        }
        
        ArrayList<String> list2 = new ArrayList<>();
        
        //Khai bao magn chua nhieu kieu du lieu: int, String, char, ...
        ArrayList<?> list3 = new ArrayList<>();
    }
}

#Main.java

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package aptech.lesson02;

/**
 *
 * @author Diep.Tran
 */
public class Main {
    String k = "OKOK";//global => dc su dung => tat func trong class
    
    static enum STUDENT_STATUS {LEARNING, PENDING, DROPOUT}

    public static void main(String[] args) {
        int x = 5;
        String s = "Sinh vien Aptech";
        
        final String s1 = "ABC";
        
        //Quan ly trang thai cua bong den: ON <=> OFF
        boolean STATUS = true;//ON, false => OFF
        int status = 1;//1 => ON, 0 => OFF
        
        //status sinh vien: LEARNING, DROPOUT, PENDING
        int studentStatus = 0;//0 -> PENDING, 1 -> LEARNING, 2 -> DROPOUT
        
        //Gay kho khan cho phan doc code.
        switch(studentStatus) {
            case 0:
                
                break;
            case 1:
                
                break;
            case 2:
                
                break;
        }
        
        STUDENT_STATUS stdStatus = STUDENT_STATUS.LEARNING;
        switch(stdStatus) {
            case LEARNING:
                
                break;
            case PENDING:
                
                break;
            case DROPOUT:
                
                break;
        }
        
        int num1 = 1;
        int num2 = 30;
        
        while(++num1 < --num2) {
            System.out.println("num1 = " + num1 + ", num2 = " + num2);
        }
        
        System.out.println("num1 = " + num1);
        
        for (int i = 0; i < 10; i++) {
            System.out.println("i > " + i);
        }
        
        int i;
        for (i = 0; i < 10; i++) {
            System.out.println("i > " + i);
        }
        
        showMenu();
    }
    
    public static void showMenu() {
        System.out.println("Hello ABC");
    }
}