#Main.java

/*
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 * and open the template in the editor.
 */
package lesson08;

import java.util.Scanner;

/**
 *
 * @author DiepTV
 */
public class Main {

    public static void main(String[] args) throws Exception {
        Scanner scan = new Scanner(System.in);
        
        int[] t = new int[3];
        //length: 3, index: 0 -> 2
        t[0] = 7;//Dung -> ko gap van de j
//        t[3] = 10;
//        System.out.println("t[3] = " + t[3]);
        System.out.println("Nhap x: ");
        int x = scan.nextInt();
        System.out.println("Nhap y: ");
        int y = scan.nextInt();
        /**int s = x/y;
        System.out.println("s: " + s);*/
        //Gap thuong xuyen => ko tranh khoi duoc
        //Exception: business logic => kiem soat lai code => fix chinh xac => exception
        //Exception: khong kiem soat dc -> ket noi mang, thao tac ve (file ko ton tai, phan quyen file (r, w, a))
        //Khong kiem soat -> bo qua -> bo qua exception -> chuong trinh van chay bt hoac dua ra thong bao.
        /**System.out.println("Nhap x: ");
        x = scan.nextInt();
        System.out.println("Nhap y: ");
        y = scan.nextInt();*/
        /**if(y == 0) {
            System.out.println("Ko duoc phep chia cho 0 -> kiem tra du lieu");
        } else {
            s = x/y;
            System.out.println("s: " + s);
        }*/
        /**try {
            //Bat dau xu ly
            //Khoi tao rat nhieu tai nguyen => yeu cau can xoa di => sau khi su dung xong.
            s = x/y;
            System.out.println("s: " + s);
            //Ket thuc xu ky ko gap exception
            //Neu dat xoa tai nguyen o day => miss => neu nhu xay ra exception => khong goi dc.
//            x = 0;
//            y = 0;
//            s = 0;
//            System.out.println("Xoa thanh cong.");
        } catch(Exception e) {
            //Khi trong try -> xay ra exception
            System.err.println("Error...");//Biet exception => message cho nguoi dung biet.
        } finally {
            x = 0;
            y = 0;
            s = 0;
            System.out.println("Xoa thanh cong.");
            //Gap exception hay ko -> deu goi vao khoi code nay
            System.out.println("finish");
            //Do vay de an toan => se la noi de xoa toan bo tai nguyen
        }*/
        
        try {
            int s = x/y;
            t[3] = 10;
        } catch(ArithmeticException e) {
            System.out.println("Error > ArithmeticException ...");
            e.printStackTrace();
        } catch(ArrayIndexOutOfBoundsException e) {
            System.out.println("Error > ArrayIndexOutOfBoundsException ...");
            e.printStackTrace();
        } catch(Exception e) {
            e.printStackTrace();
            System.out.println("TH ko biet nguyen nhan loi do dau -> bat loi va kiem tra.");
        } finally {
            System.out.println("Ket thuc");
        }
        throw new Exception("Test throws");//chuong trinh dang chay -> die.
        //business logic => die => dev => biet fix.
//        System.out.println("Finish program");
    }
    
    public void test() {
        Student std = new Student();
        std.input();
    }

    /**
     * inner class => thong thuong no la cac class trong class cha.
     */
    public class Student {
        String name, address;

        public Student() {
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public String getAddress() {
            return address;
        }

        public void setAddress(String address) {
            this.address = address;
        }
        
        public void input() {
            System.out.println("Nhap ...");
        }
    }
}

#Test.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 lesson08;

/**
 *
 * @author DiepTV
 */
public class Test {
    public static void main(String[] args) {
        String s1 = "ABC";
//        s1 = new String("Xin chao");//Khong nen khai bao bien theo cach nay.
        System.out.println("s1: " + s1);
        s1 = s1 + " XYZ";
        s1 = s1.concat("OKOK");
        System.out.println("s1: " + s1);
        
        //Quan ly du lieu string phuc tap
        /**
         * Add du lieu => tu dong mo rong khong gian bo nho => cham hon buffer => quan ly tai nguyen tot hon buffer
         */
        StringBuilder builder = new StringBuilder();
        builder.append("A1");
        builder.append("A2");
        builder.append("A3");
        builder.append("A4");
        builder.append("A5");
        builder.append("A6");
        //insert, delete, ...
        
        System.out.println(builder.toString());
        
        /**
         * Quan ly nhanh => ton tai nguyen
         */
        StringBuffer buffer = new StringBuffer();
        buffer.append("B1");
        buffer.append("B2");
        buffer.append("B3");
        buffer.append("B4");
        buffer.append("B5");
        buffer.append("B6");
        
        System.out.println(buffer.toString());
    }
}

#Test2.java

/*
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 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package lesson08;

import java.util.Scanner;

/**
 *
 * @author DiepTV
 */
public class Test2 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        
        System.out.println("Nhap x: ");
        float x = scan.nextInt();
        System.out.println("Nhap y: ");
        float y = scan.nextInt();
        
        float s;
        try {
            s = Calculator.chia(x, y);
            System.out.println("s: " + s);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        System.out.println("Hoan thanh code");
    }
}

#Calculator.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 lesson08;

/**
 *
 * @author DiepTV
 */
public class Calculator {
    public static float cong(float x, float y) {
        return x + y;
    }
    
    public static float tru(float x, float y) {
        return x - y;
    }
    
    public static float nhan(float x, float y) {
        return x * y;
    }
    
    public static float chia(float x, float y) throws Exception {
        if(y == 0) {
            throw new Exception("Loi chia cho 0 -> Vui long sua loi nay!!!");
        }
        
        return x / y;
    }
}