Download Variabel, Tipe Data & Operator

Variabel, Tipe Data &
Operator
Teguh Sutanto, M.Kom.
Buku Hari ini
Menu Hari ini
• Review basic programing
• Variable
• Tipe Data
• Operator
Statement & Ekspression
• Java statements appear inside methods and classes; they describe all
activities of a Java program.
• Expressions produce values; an expression is evaluated to produce a
result that is to be used as part of another expression or in a
statement.
Variable
• A variable is a named memory location capable of storing data of a
specified type
• A variable must be declared before it can be used.
• A variable declaration specifies:
• the type of data that the variable can hold, for example int or double , and
• the name of the variable.
• When naming a variable, you should choose a name that is
meaningful.
• A variable may be declared and given an initial value with a single
initialization statement.
Declaring Variables
• must start with a letter (A to Z, a to z) or (unusually) an underscore
‘_’;
• can contain any number of letters or digits (a digit is 0 to 9);
• can contain the underscore ‘_’;
• can be up to 255 characters long.
Legal
namaDepan
no_telp
min123
Ilegal
123Nama
no telp
%area
Constant
• A constant is a value that never changes
• In Java, a constant is a field with a particular set of modifiers: static
and final. Most are also public, though it is possible (and sometimes
useful) to have private, package, and protected constants.
Tipe Data
Isi Data
Boolean
boolean
Numerik
Floating
Point
Integer
Text
String
Char
Memasukan Data Dari Luar
Program
Menggunakan class java.util.Scanner
• Include the import statement: import java.util.*;
• Declare a Scanner object as Scanner name = new Scanner(System.in)
• Methods
•
•
•
•
•
•
name.nextLong() //membaca data dengan tipe long
name.nextDouble() //membaca data dengan tipe double
name.nextFloat() //membaca data dengan tipe float
name.nextBoolean() //membaca data dengan tipe boolean
name.nextInt() //membaca data dengan tipe int
name.nextShort() //memcaca data dengan tipe short
Problem Statement Write an application that
prompts for the number of pizzas and
the number of toppings. The program should
calculate the price of the pizza (including
sales tax) and print a receipt.
Operator di Java
Kategori
Operator
postfix
unary
casting
Multiplicative
additive
shift
relational
expr++ expr-++expr --expr +expr -expr ~ !
(type)
*/%
+<< >> >>>
< > <= >= instanceof
Operator di Java (lanjutan…)
Kategori
Operator
equality
Bitwise AND
bitwise exclusive OR
bitwise inclusive OR
Logical AND
logical OR
Ternary
assignment
== !=
&
^
|
&&
||
?:
= += -= *= /= %= &= ^= |= <<= >>= >>>=
Opertor
++eks
--eks
+eks
Nama Operator
Prefix Increment
Prefix Decrement
Unary plus
-eks
~
Unary minus
Bitwise
complement
Logical complement Membalik true dan false
!
Keterangan
Penambanan 1 dari nilai ekspresi
Pengurangan 1 dari nilai ekspresi
Mengindikasikan sebuah bilangan
positive
Membuat negative nilai ekspresi
Membalik nilai integer per bit
Multiplicative Operator
multiplication (*)
division (/)
modulus (%).
Lat2: Celsius to Fahrenheit
• The temperature F in Fahrenheit equals (9 / 5) C +32 where C
is the Celsius temperature. Write a program that computes
and displays the temperatures in Fahrenheit for Celsius
values 5, 0, 12, 68, 22.7, 100, and 6.
Lat 2: JamMenitDetik
•Buatlah program yang meminta user untuk
memasukan jumlah detik, kemudian
program akan menghitung berapa jam,
berapa menit dan berapa detik.
•Diskusikan dengan kelompok anda,
kemudian buatlah programnya
Lat 3:Uptime
• The uptime command of the UNIX operating system displays the
number of days, hours, and minutes since the operating system was
last started. For example, the UNIX command uptime might return
the string Up 53 days 12:39
• Write a program that converts the 53 days, 12 hours, and 39 seconds
to the number of seconds that have elapsed since the operating
system was last started.
• Catatan masukan variable:
• totalHari
• totalJam
• totalMenit
Casting
• Software developers often find that they need a variable of one type
to be a variable of another type. In Java (and most programming
languages), you can't change the type of a variable. Instead, you
should create a new variable and convert the existing variable into
the new variable's type. That process is called casting, and Java
provides an operator of sorts for doing it. I say, “of sorts,” because the
casting operator differs according to the data type to which you're
casting.
Relational Operators
• The relational operators compare things to one another. In particular,
they determine whether one value is greater than, less than, equal to,
or not equal to another value.
• For the relational operators to work, the items being compared have
to be comparable.
• > (greater than), < (less than), >= (greater than or equal to), and <=
(less than or equal to) all work on primitives, but they don't work on
objects.
RelationOprDemo.java
Equality Operators
• Java has two equality operators:
• == (equals)
• != (not equals).
Bitwise AND Operator (&)
• The bitwise AND operator (&) compares two binary values and sets
each bit to 1 where each bit in the two values being compared is 1
Bitwise AND
Variable
Desimal
Binary
bil1
85
1
0
1
0
1
0
1
bil2
63
0
1
1
1
1
1
1
result
21
0
0
1
0
1
0
1
Bitwise Inclusive OR Operator (|)
• The bitwise Inclusive OR operator (|) compares two binary values and
sets each bit to 1 if either bit is 1
Bitwise OR
Variable
Desimal
Binary
bil1
85
1
0
1
0
1
0
1
bil2
63
0
1
1
1
1
1
1
result
127
1
1
1
1
1
1
1
Bitwise Exclusive OR Operator (^)
• The bitwise Exclusive OR (often shortened to XOR) operator (^)
compares two binary values and sets each bit to 1 if the bits differ.
Bitwise XOR
Variable
Desimal
Binary
bil1
85
1
0
1
0
1
0
1
bil2
63
0
1
1
1
1
1
1
result
106
1
1
0
1
0
1
0
Logical AND Operator (&&)
• The logical AND operator (&&) returns true if both arguments are
true and false if either one is false
Logical OR Operator (||)
• The logical AND operator (||) returns true if either of its arguments
are true and false only if both arguments are false.
Assignment Operators
• The assignment operators set values and assign object references.
The basic assignment operator (=) is by far the most often used
operator
• Every time we put something like int = 0 (assigning a value to
aprimitive) or Date now = new Date() (assigning an object reference
to a variable) into an example, we use the basic assignment operator.
Operator
=
Description
This is the basic assignment operator.
+=
Add the right-hand operand to the left-hand operand and assign the result to the
left-hand
operand. x += 2 is the same as x = x + 2.
-=
Subtract the right-hand operand from the left-hand operand and assign the result to
the lefthand operand. x -= 2 is the same as x = x – 2.
*=
Multiply the right-hand operand by the left-hand operand and assign the result to
the lefthand operand. x *= 2 is the same as x = x * 2.
/=
Divide the right-hand operand by the left-hand operand and assign the result to the
left-hand operand. x /= 2 is the same as x = x / 2.
%=
Use the right-hand operand to determine the modulus of the left-hand operator and
assign the result to the left-hand operator. x %= 2 is the same as x = x % 2.
Operator
&=
Description
Perform a bitwise and operation and assign the result to the left-hand operator. x
&= y is the same as x = x & y.
|=
Perform a bitwise inclusive operation and assign the result to the left-hand
operator. x |= y is the same as x = x | y.
^=
Perform a bitwise exxclusive or operation and assign the result to the left-hand
operator. x ^= y is the same as x = x ^ y.
<<=
Perform a bitwise left-shift operation and assign the result to the left-hand
operator. x <<= y is the same as x = x << y.
>>=
Perform a bitwise right-shift operation and assign the result to the left-hand
operator. x <<= y is the same as x = x >> y.
>>>=
Perform a bitwise signed right-shift operation and assign the result to the lefthand operator. x >>>= y is the same as x = x >>> y