-char and string

finding the ASCII code:

import javax.swing.JOptionPane;

public class W09Chars {
public static void main(String[] args) {
char ch=’A';
byte b=65;

JOptionPane.showMessageDialog(null, “ASCII code of character” + ch + ” is ” + (int)ch);
JOptionPane.showMessageDialog(null, “Character with ASCII code” + b + ” is ” + (int)ch);
JOptionPane.showMessageDialog(null, ch + ” is ” + ((ch > b) ? “bigger” : “smaller”) + “than” + (char)b);
}
}

Finding Vowel:

import javax.swing.JOptionPane;

public class Vowel {
public static void main(String[] args) {
String name=”AKU Hebat”;
int panjangg=0;

int panjang = name.length();

for (int i=0 ; ifalse
word1.equals(word2) –> –>true

*String word1 = “Surabaya”
String word2 = “Suralaya”

cara compare:
word1==word2 –> –>false
word1.equals(word2) –> –>false

-pattern matching:

import javax.swing.JOptionPane;

public class W09ValidateClassname {
private static final String STOP=”STOP”;
private static final String VALID=”VALID”;
private static final String INVALID=”INVALID”;

private static final String VALID_PATTERN
= “[A-Z][a-zA-Z0-9_]*”;

public static void main(String[] args){
String input,output;

while (true){
input = JOptionPane.showInputDialog(null,”Class name :”);

if(STOP.equals(input))
break;

if(input.matches(VALID_PATTERN))
output = VALID;
else
output = INVALID;

JOptionPane.showMessageDialog(null, output);
}

}
}

-using keyword this
see the difference:

1.
public class Rectangle{
private double length;
private double width;

public Rectangle(){
//do nothing
}
public void setLength(double l){
length=l;
}
public void setWidth(double w){
width=w;
}
}

2.
public class Rectangle1{
private double length;
private double width;

public Rectangle1(){
//do nothing
}
public void setLength(double length){
this.length=length;
}
public void setWidth(double width){
this.width=width;
}
}

(if you use the same argument name with the class name, you have to use this keyword)

examine this following snippet
- Rectangle kotak = new Rectangle()
- Rectangle is class method, owned by class, no need for isntantiation
- to use : Rectangle.ClassMethod();
- kotak = object, the instance method, owned by instance, need instantiation to use
- to use : kotak.InstanceMethod();

information hiding:
-public and private modifiers designate the accesibility of class components
-we need to use methods to access it

passing parameters:
-check the method that you want to call (must match with the signature)
-using the same name with what you declare (same data type too)

get the return from methods:
public double getBalance(){
//do some process

return balance;
}

make class Account:
public class Account{
private double balance;
private String ownerName;
private int accNumber;

public Account(int newAccNumber, String newOwnerName, double newBalance) {
setData(newAccNumber, newOwnerName, newBalance);
}
public void print() {
System.out.println(“[" + accNumber + " " + ownerName + "]=” + balance);
}
public void setBalance(double newBalance) {
balance = newBalance;
}
public void setOwnerName(String newOwnerName) {
ownerName = newOwnerName;
}
public void setAccNumber(int newAccNumber) {
accNumber = newAccNumber;
}
public void setData(int newAccNumber, String newOwnerName, double newBalance){
setAccNumber(newAccNumber);
setOwnerName(newOwnerName);
setBalance(newBalance);
}
public double getBalance() {
//do some process

return balance;
}
}

make the TrxRunner:
public class TrxRunner {
public static void main(String[] args){
// declaration
Account acct1 = new Account(10001 , “Stone Giant” , 0.);

// initialization
acct1.setData(10001 , “StoneGiant” , 0.);

// usage
acct1.print();

// add money
acct1.setBalance(100.);

// usage
System.out.println(“Current Balance= ” + acct1.getBalance());
}
}

–> the result is:
[10001 StoneGiant]=0.0
Current Balance= 100.0

make ExPassByRef:
public class ExPassByRef {
public void modify(int a, Account acct) {
a += 10;
acct.setOwnerName(“Windrunner”);
}

public static void main(String[] args){
int x = 0;
Account acct1 = new Account(10001, “Stone Giant”, 0.);

System.out.println(“x=” + x);
acct1.print();

new ExPassByRef().modify(x, acct1);

System.out.println(“x=” + x);
acct1.print();
}
}

the result is–>
x=0
[10001 Stone Giant]=0.0
x=0
[10001 Windrunner]=0.0

Question:
1. A submarine can be used for 100 people. One day, a pregnant woman come and use that.
a few minutes after go, the ship is drowning. Why is that??
2. Redo has just finished digging a hole. The hole is about 2x length, y depth, and 3z width.
find the volume of sands inside the hole if y=2x, y=z, z=2x!

thats all for today!!

- can’t do the test.
- given a lot of examples
>simplest code
public class Simplest{
public static void(String[] args){
//do nothing(cant be ran without method)
}
}

>next calculate
public class Calculate{
public static void main(String[] args){
//set the value
int income = 500000, expense = 270000;
float base = 2.7f;
float height;
int saldo;
float area;

height = 3.1f;

//calculate
saldo = income – expense;
area = (float)1/2 * base * height;

//print out the result
System.out.println(“My money now = ” + saldo);
System.out.println(“Triangle area = ” + area);
}
}
and you should got:
My money now = 230000
Triangle area = 4.185

>next age
public class CrossType{
public static void main(String[] args){
int age;
age = Integer.parseInt(args[0]);
age += 5;
System.out.println(“Your age 5 years later : ” + age);
}
}

>next standart IO
import java.util.Scanner;
public class MyScanner{
public static void main(String[] args){
System.out.print(“Your age is now = “);
Scanner myScanner = new Scanner(System.in);
int age = myScanner.nextInt();
age += 5;
System.out.println(“In the 5 years, your age will be ” + age);
}
}

>next math class
import java.util.Scanner;
public class MyMath{
public static void main(String[] args){
double num, x, y;
. . .
num = Math.sqrt(Math.max(x,y) + 3.14);
}
}

>next gregorian calendar
import java.util.GregorianCalendar;
public class MyCalendar{
public static void main(String[] args){
GregorianCalendar now = new GregorianCalendar();
System.out.println(” today is ” + now.get(now.DATE) +
“/” + now.get(now.MONTH) +
“/” + now.get(now.YEAR));
}
}

- cases: make the degree converter between reamur and celcius, farenheit and celcius, and kelvin and celcius!!
R = c*0.8
F = c*1.8+30
K = c+273
public class DegreeConverter{

public double getReamur(int celcius){
return celcius*0.8;
}
public double getFarenheit(int celcius){
return celcius*1.8 + 30;
}
public double getKelvin(int celcius){
return celcius+273;
public static void main(String[] args){
DegreeConverter x = new DegreeConverter();

System.out.println(x.getReamur(50) + ” ” + x.getFarenheit(50) + ” ” + x.getKelvin(50));

}
}

task:
-declare why that?? (getReamur, return, etc)
-download and install netbeans
-get tutorial video on how to use netbeans

thats all for today..

1.Last week Review
-The movie WE 2010 and the UML created based on the movie

2.Read the pdf taken from e-learning
-OOP tutorial
-UML tutorial

3.Exercise
-Create the UML and the coding based on a story given

4.What’s new??
-if you want to create a line that is not a part of your java code, use: //
-if you want to create a paragraph that is not a part of your java code, use: /* and end it with: */
-in java, print using System.out.println(…)
-if you want to go to a disk, then just type the disk (ex: D:) (see the picture)
-if you want to go to a specific folder, then use the changedirectory (ex: cd oop) -> it will go to oop folder (see the picture)
-if you have your java parts all in one folder, and you want to run them all, you dont need to compile them one by one, just use javac *.java and it will compile all your java files on that folder (see the picture)

5.What is javac ??
-Command to compile java files
ex: javac Controller.java
-after you run it with javac, you will automatically have .class file (Controller.class)

6.What is java ??
-Command to run a program
ex: java Controller

That’s All for this week, thank you.