9/12/2015IT 2751 IDE ( Integrated Development Environment ) 1.A customized plain text editor 2.Compiler 3.Loader 4.Debugging tool JDK (Java Development Kit) = IDE+JRE Eclipse = IDE 1.vi (or emacs) 2.javac hello.java 3.java hello

9/12/2015IT 2752 Problems  Solutions cycle Problems System analyst, Project leader Algorithms Senior Programmers Programs in JAVA (or any high level Programming Language) compiler Assembly Assembler Machine code linker Results Customers Programmers Syntax Semantics (human) IDE (computers) VM

9/12/2015IT 2753 Procedure- v. Object- oriented To solve a program is: To find a way to manipulate data -- We design procedures Procedure-Oriented Programming Statements + functions  programs To find objects to model the problem – We choose data (object) Object-Oriented Programming Classes + Objects  programs (interfaces, methods, attributes…)

9/12/2015IT 2754 Robot int street int avenue Direction direction ThingBag backbag... Robot(City aCity, int aStreet, int aAvenue, Direction aDir) void move() void turnLeft() void pickThing() void putThing()... Services, methods Attributes UML class diagram for Robot Class name Constructor

9/12/2015IT 2755 Modeling what? Modeling Robots in a City with Software Classes. Robot int street int avenue Direction direction ThingBag backbag... Robot(City aCity, int aStreet, int aAvenue, Direction aDir) void move() void turnLeft() void pickThing() void putThing()... City String name int stree_No int ave_No City( )....

6 import javax.swing.JOptionPane; public class time{ public static void main(String args[]){ int x,y,z; String X,Y; X = JOptionPane.showInputDialog("Input x"); Y = JOptionPane.showInputDialog("Input y"); x = Integer.parseInt(X); y = Integer.parseInt(Y); z = x*y; JOptionPane.showMessageDialog( null, x + " * " + y + " = " + z, "The product of " + x + " and " + y, JOptionPane.PLAIN_MESSAGE ); System.exit(0); } classes methods package arguments Variable declaration class defined in the package 9/12/2015 IT 275 Anatomy of a Java Program

9/12/2015IT 2757 Task: deliver X from (1,2) to (3,1) and step away X import becker.robot.*; public class DeliverX{ public static void main(String args[]){ // set up Initial situation City A = new City(); Thing X = new Thing(A,1,2); Robot karel = new Robot(A,0,0, Direction.East); // direct the robot karel.move(); karel.turnLeft(); karel.move(); karel.pickThing(); karek.move(); karel.move(); karel.turnLeft(); karel.move(); karel.putThing(); karel.move(); } named Karel

9/12/2015IT 2758 import becker.robot.*; public class DeliverX{ public static void main(String args[]){ // set up Initial situation City A = new City(); Thing X = new Thing(A,1,2); Robot karel = new Robot(A,0,0,Direction.East); // direct the robot karel.move(); karel.turnLeft(); karel.move(); karel.pickThing(); karek.move(); karel.move(); karel.turnLeft(); karel.move(); karel.putThing(); karel.move(); } Anatomy of a Java Program

9/12/2015IT 2759 Package: collection of classes // Java API: Java Application Programming Interface // (java., javax.) // GUI: Graphical User Interface // // using swing package, JOptionPane class // showMessageDialog method import javax.swing.JOptionPane; public class TestPane{ public static void main(String args[]){ JOptionPane.showMessageDialog( null, "Welcome\nTo\nswing\nPackage"); System.exit(0); }

9/12/2015IT A Java Program: // Text-printing program. public class Welcome1 { // main method begins execution of Java application public static void main( String args[] ) { System.out.println( "Welcome to Java Programming!" ); } // end method main } // end class Welcome1 /********************************************************* *(C) Copyright by * * * **********************************************************/

9/12/2015IT Reusing Codes 1.Composition 2.Inheritance A class has another class, “has a” relation A class inherits another class, “is a” relation A car has an engine An SUV is a car

9/12/2015IT Composition: has a A DeliverX has a main, The main has a City, Thing, and a Robot import becker.robot.*; public class DeliverX{ public static void main(String args[]){ // set up Initial situation City A = new City(); Thing X = new Thing(A,1,2); Robot karel = new Robot(A,0,0, Direction.East); }

9/12/2015IT Composition: has a A BankAccount has a Client, has a List of BankTransaction public class BankAccount { private Client client; private List transactions; // other fields... }

9/12/2015IT Classes: A class is a concept of something Vehicle 4 wheels, seats, engine, windows, color…… accelerate, start, stop, turn, lock, Truck ………… Sedan ………… SUV ………… Matrix ………… Focus …………

9/12/2015IT Inheritance: From membership point of view Vehicle SUV Honda Pilot Object Number Integer Double Base concept Derived concept Java Base class Derived class A SUV is a vehicle, but a vehicle may not be a SUV Any SUV is a Vehicle

9/12/2015IT Inheritance: From functionality point of view SUV Vehicle Derived class Base class All vehicle can do, SUV can too The SUV has every properties and function of the Vehicle

9/12/2015IT UML (Unified Modeling Language) Diagram Vehicle TruckSedanSUV MatrixFocus Honda Pilot Matrix XRS

9/12/2015IT A - my_a: int +get_a():int B - my_b: int +get_b():int B - my_b: int +get_a():int +get_b():int = my_a is invisible to B

9/12/2015IT Base class (superclass) & Derived class (extended subclass) // A is a base class public class A { private int my_a; Public A(int a) { my_a = a; } public int get_a() { return my_a; } // B is a derived class Public class B extends A { private int b; public B(int a, int b) { super(a); this.b = b; } public int get_b() { return b; } A a = new A(2); B b = new B(3,7); I = a.get_a(); J = b.get_a(); K = b.get_b(); B inherits A’s functions and variables.

9/12/2015IT An enhanced robot Robot int street int avenue Direction direction ThingBag backback Robot(City aCity, int aStreet, int anAvenue, Direction aDir) void move() void turnLeft() void pickThing() void putThing() ExperimentRobot ExperimentRobot(City aCity, int aStreet, int anAvenue, Direction aDir) void turnAround(); void turnRight(); void move3(); = ExperimentRobot int street int avenue Direction direction ThingBag backback ExperimentRobot(City aCity, int aStreet, int anAvenue, Direction aDir) void move() void turnLeft() void pickThing() void putThing() void turnAround(); void turnRight(); void move3();

9/12/2015IT Selection sort algorithm in Java public static class SelectionSort { public void sort(int a[]) { for (int i = 0; i<a.length-1; i++) { // select one for a[i] int j = min(a,i); exchange(a,i,j); } // select the minimum between a[s] to the end private int min(int a[], int s) {int m = s; for (int i=s; i<a.length;i++) if (a[i] < a[m]) m=i; return m; } private void exchange(int[] a, int i, int j) { int temp = a[i]; a[i] = a[j]; a[j] = temp; } } // end of SelectionSort