Data Type & Input/Output Session 3

Data Type & Input/OutputSession 3 Course : T0974-Algorithm & Object-Oriented Programming I Year : 2010

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

JAWABAN QUIZ class Hitung{int bolos=0;int total=0;int basic=0;inttunjangan=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);}} public class Gaji{public static void main(String [] args){Hitung h= new Hitung(); //membuatobyekdari //kelasHitungh.basic=5000000;h.tunjangan=1500000;h.bolos=2;h.hitung();}}

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

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)

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

DataType

Data Type Filename : TipeData.java Output:

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.

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

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);

Input / Output (I/O)

Input / Output (I/O) • Note : • ˽  spasi

Input / Output (I/O)

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

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

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.

Type Casting (Conversion)

Type Casting (Conversion) • Conversion from String to Atomic data type can be done by class helper.

Type Casting (Conversion)

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.

ASCII

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.

Type Casting (Conversion) cont.

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;

Constant

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.

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

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.

Advanced Learning

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)

Latihan Kembangkanjawaban quiz untukterima input dari keyboard menggunakanKelas Scanner

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

Data Type & Input/Output Session 3