Download Basic Java Programming

Basic Java Programming
Teguh Sutanto, M.Kom.
Tujuan
• Mahasiswa dapat menyebutkan berbagai tipe data dan operato
Materi
• Struktur dasar program Java
• Variable
• Constanta
• Tipe Data
• Operator
Buku Referensi
•A computer program or
application is a set of instructions,
written in a programming
language that enables a computer
to perform some specifi ed task
Mengapa Java?
• Java is small and beautiful
• Java is object oriented
• Java supports the Internet
• Java is general purpose
• Java is platform independent
• Java has libraries
Struktur Program Java
Method main(String []argz)
Local variable
Nama Class (Nama Program)
Isi program “{ }”
Penamaan Program/Class
• Kata Benda
• Diawali dengan HurufBesar
• Nama File = NamaProgram
• Contoh: public class ProgramPertamax disimpan dengan nama
ProgramPertamax.java
• Tidak boleh ada spasi
• Contoh: Program Pertamax
• Tidak boleh diawali dengan angka
• Contoh: 1Program
Method public static void main(String
[]param)
Parameter Program
public static void main(String []param){
//code program
//alur program
}
Setiap program yang akan
dijalankan oleh JVM harus ada
method launcher yang dengan
nama main(String[] a)
Every Java application contains a class with a main method.
When the application starts, the instructions in the main method are
executed.
dengan nama PrgPertamax.java
>javac PrgPertamax.java
>java PrgPertamax
A keyword is a dictionary word — a word
that’s built right into a language
Keywoards
abstract
switch
package
if
double
byte
throws
return
int
final
class
volatile
super
continue
assert
do
private
implements
else
case
transient
short
interface
finally
const
while
for
default
synchronized
this
protected
import
enum
catch
try
static
long
float
s
new
goto
boolean
break
throw
public
instanceof
extends
char
void
strictfp
native
e
Alur Program
1.
2.
3.
4.
5.
6.
sequences
repetitions
selections
methods
ready-made objects
objects you write yourself
Case Sensitive
• The java proGRAMMing lanGUage is case-sensitive. ThIS MEans that if
you change a lowerCASE LETTer in a wORD TO AN UPPercase letter,
you chANge the wORD’S MEaning. ChangiNG CASE CAN MakE the
enTIRE WORD GO FROM BeiNG MEANINGFul to bEING MEaningless.
public static void main(String args[]) {
System.out.println(“Chocolate, royalties, sleep”);
}
• main: The main starting point for execution in every Java program.
• String: A bunch of text; a row of characters, one after another.
• System: A canned program in the Java API. (This program accesses
some features of your computer that are outside the direct control of
the Java virtual machine (JVM).)
• out: The place where a text-based program displays its text. (For a
program running in Eclipse, the word out represents the Console
view.
• println: Display text on your computer screen
Variable: The Holders of
Information
• Sebuah tempat untuk menyimpan data, contoh:
• Angka 365 merepresentasikan jumlah hari dalam satu
tahun
• Angka 37 derajat celcius menunjukkan suhu normal
tubuh manusia
• Nama seorang aktor favorit, Jet Lee
Variable di mata seorang programer
JumlahHari
suhuTubuh
Programmer
aktorFavorit
Variables in algebra are letters of the alphabet, like x and y, but in computer
languages, they can also be any descriptive names like sum, answer, or
first_value.
A variable is a named memory
location capable of storing data of
a specified type
So…what is the var?
• Computer programs manipulate (or process) data.
A variable is used to store a piece of data for processing. It
is called variable because you can change the value stored.
• More precisely, a variable is a named storage location, that
stores a value of a particular data type. In other words,
a variable has a name, a type and stores a value.
• A variable has a name (or identifier),
e.g., radius, area, age, height. The name is needed to
uniquely identify each variable, so as to assign a value to
the variable (e.g., radius=1.2), and retrieve the value stored
(e.g., radius*radius*3.1416).
Variable…(cont)
• A variable has a type. Examples of type are:
• int: for integers (whole numbers) such as 123 and -456;
• double: for floating-point or real numbers, such
as 3.1416, -55.66, having an optional decimal point and
fractional part;
• String: for texts such as "Hello", "Good Morning!". Text
strings are enclosed within a pair of double quotes.
Integers
Floating-point
•
•
•
•
byte
short
int
long
• float
• double.
Characters
• This group includes char, which represents symbols in a
character set, like letters and numbers.
Boolean
• This group includes boolean, which is a special type for
representing true/false values.
Deklarasi Variable
• A variable must be declared before it can be used.
• A variable declaration specifi es
• the type of data that the variable can hold, for example int
or double , and
• the name of the variable.
varType varName; // Declare a variable of a type
varType varName1, varName2,...; // Declare multiple variables of the same type
varType varName = initialValue; // Declare a variable of a type, and assign an initial
value
varType varName1 = initialValue1, varName2 = initialValue2,... ; // Declare variables
with initial values
• A variable can store a value of that particular type. It is important to
take note that a variable in most programming languages is
associated with a type, and can only store value of the particular
type. For example, a int variable can store an integer value such
as 123, but NOT real number such as 12.34, nor texts such
as "Hello". The concept of type was introduced into the early
programming languages to simplify intrepretation of data made up
of 0s and 1s.
Contoh Variable
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