Data Type & Input/OutputSession 3

Course : T0974-Algorithm & Object-Oriented Programming IYear : 2010

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Learning Outcomes

After taking this course, student should be expected to be able to apply data types depend on the need of the programs and using syntax for Input – Output Operation

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JAWABAN QUIZ

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public class Gaji{public static void main(String [] args){

Hitung h= new Hitung();  //membuat obyek dari //kelas Hitung    h.basic=5000000;    h.tunjangan=1500000;    h.bolos=2;    h.hitung();}}

class Hitung{int bolos=0;int total=0;int basic=0;int tunjangan=0; String nama="RINA";void hitung(){if (bolos<=3)    {        total=basic+tunjangan;    }    else    {        total=basic;    }System.out.println ("Nama " + nama+ " Jumnlah bolos:" + bolos);    System.out.println ("Gaji :" + total);}}

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Outline Materi

• Data Types• Input/Output (I/O)• Output Format• Type Casting (Conversion)• ASCII• Import• Constant

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Data Type

• An attribut that has range value and type.• To be used as a value storage from execution

process.• Based on its data type :

– Boolean (boolean)– Numeric (byte, short, int, long, float, double)– Character (char)– String (String)

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Data Type

• Based on Complexity :– Atomic DT (boolean, byte, char, short, int, long, float,

double)– Composite DT (Array, Struct, List, Queue, Stack, String,

Tree)• Based on Source:

– Native / primitive / basic DT– Abstract DT

• Based on Customization:– Built-in DT– User-defined DT

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Data TypeName Range Size Class

boolean

true, false 1 bit Boolean

byte -27 (-128) to 27 – 1 (127)

8 bit Byte

char 0 to 65,535 16 bit Character

short -215 (-32,768) to 215 – 1 (32,767)

16 bit Short

int -231 (-2,147,483,648) to 231 (2,147,483,647)

32 bit Integer

long -263 to 263 – 1 64 bit Long

float -3.4E38 to 3.4E38 32 bit Float

double -1.798E308 to 1.798E308

64 bit Double

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Data Type

Filename : TipeData.java

Output:

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Input / Output (I/O)

• A Communication between computer to other entity (Human / Machine)

• Input: Signal/Data will be recevied by system.• Output: Signal/Data will be sent from system.• I/O perform or I/O operation.

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Input / Output (I/O)

• Input Devices e.g. : keyboard, mouse• Output Devices e.g. : monitor, printer• I/O Devices e.g. : disk, file

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Input / Output (I/O)

• Get input from console using Scanner.• Library java.util.Scanner.• It needs to import declaration :

import java.util.Scanner;• Afterward declare an object creation :

Scanner input = new Scanner(System.in);

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Input / Output (I/O)

Method Usenext(); Input String (word)

nextLine(); Input String (sentence)

nextByte(); Input number (byte)

nextShort(); Input number (short)

nextInt(); Input number (int)

nextLong(); Input number (long)

nextFloat(); Input number (float)

nextDouble(); Input number (double)

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Input / Output (I/O)

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Input / Output (I/O)

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Input / Output (I/O)

Specifier

Description Example

Output

%b boolean %6b ˽false˽˽true

%c character %5c ˽˽˽˽a

%d integer %5d ˽˽˽691234567

%f Floating-point

%5.2f ˽˽3.14˽20.60

%e scientific %10.2e ˽˽3.14e+02

%s string %10s ˽˽˽˽˽hello

• Note :˽ spasi

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Input / Output (I/O)

Specifier

Description Example

Output

%b boolean %-6b false˽true˽˽

%c character %-5c a˽˽˽˽

%d integer %-5d 69˽˽˽1234567

%f Floating-point

%-5.2f 3.14˽˽20.60˽

%e scientific %-10.2e

3.14e+02˽˽

%s string %-10s hello˽˽˽˽˽• Note :

˽ spasi

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Input / Output (I/O)

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Input / Output (I/O)

• System.out.print print into console without linefeed (newline).

• System.out.println print into console with linefeed (newline)

• System.out.printf same as System.out.print, supports format output

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Type Casting (Conversion)

• Convert a value to different type.• Type casting conversion :

– Widening a type: convert a value from smaller data to bigger data. (Automatically done by Java).

– Narrowing a type: convert a value from bigger data to smaller data.

• Size of data type (smallest to biggest)

byte, short, int, long, float, double

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Type Casting (Conversion)

• Parentheses is use as a syntax for narrowing.• Example 1:

– float f = (float) 10.1;– int i = (int) f;

• Example 2 :– double d = 4.5;– int i = (int) d;

• As depicted from example 1-2 above, f and d values haven’t been changed.

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Type Casting (Conversion)

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Type Casting (Conversion)

• Conversion from String to Atomic data type can be done by class helper.

Class Konversi ke tipe data

Pemakaian

Boolean boolean Boolean.parseBoolean(…);

Byte byte Byte.parseByte(…);

Character

char String.charAt(<index>);

Short short Short.parseShort(…);

Integer int Integer.parseInt(…);

Long long Long.parseLong(…);

Float float Float.parseFloat(…);

Double double Double.parseDouble(…);

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Type Casting (Conversion)

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Type Casting (Conversion)

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Type Casting (Conversion)

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ASCII

• American Standard Code for Information Interchange

• 7-bit, 128 characters (000 s/d 127)• uppercase/lowercase letters, digits, punctuation

marks, dan control characters• Next development of ASCII Unicode has

1,112,064 characters.

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ASCII

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ASCII

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ASCII

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Type Casting (Conversion) cont.

• ASCII characters from ‘0’ s/d ‘9’– ‘0’ 48– ‘1’ 49– ‘9’ 57

• Convert character to number can be done by substracting 48.

• Convert number to character can be done by adding 48.

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Type Casting (Conversion) cont.

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Constant

• a constant variable is a variable that is always constant

• Example :– π (PHI) = 3.14159 26535 89793 23846 26433 83279

50288 41971 69399 37510 – g (gravitation) = 9.8

• Constant should have been declared and initialized.

• Final is a keyword in Java to declare constant.• Declaration :

– final datatype CONSTANTNAME = VALUE;– Example: final double PHI = 3.1415;

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Constant

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Did You Know?

• For every Scanner use, it should need “import java.util.Scanner;”.

• Because Scanner is a class that should be included.

• Contrary to System library, it doesn’t use “import java.lang.System;” declaration which Java automatically import all of “java.lang” content to its new code.

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Did You Know?

• Content of java.lang which is usually used :– Boolean– Byte– Character– Double– Float– Integer– Long– Math– Short– String– System– Thread

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Advanced Learning

• Instead of scanner, BufferedReader can be used for handling input from console.

• It needs import from java.io.BufferedReader & java.io.InputStreamReader;

• And do object creation :– BufferedReader input = new BufferedReader (new

InputStreamReader(System.in));

• Either use read() method for reading single character or readLine() method for reading word.

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Advanced Learning

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Advanced Learning

• Import declaration like :import java.io.BufferedReader;import java.io.InputStreamReader;can be shortened to:import java.io.*;

• try and catch are going to be disscussed next lecture (Exception Handling)

40

LatihanKembangkan jawaban quiz untuk terima input dari

keyboard menggunakan Kelas Scanner

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References

• Introduction to Java. 7ed. 2009. Liang. p60, p67-71, p79-81, p117-118, p1300-1301

• Java Software Solutions. 5ed. 2007. Lewis. p99-103, p111-114

• The Complete Reference: Java. 5ed. 2005. Herbert. p33-48

• Dasar Pemrograman Java2. 2004. Abdul Kadir. p66-73

• Composite Data Types. http://remote.science.uva.nl/~heck/JAVAcourse/ch4

• Data Type. http://en.wikipedia.org/wiki/Data_type• Primitive Data types.

http://java.sun.com/docs/books/tutorial/java/nutsandbolts/datatypes.html

• Primitive Data types. http://en.wikipedia.org/wiki/Primitive_type