IDE (Integrated Development Environment) 5/6/2019 IDE (Integrated Development Environment) A customized plain text editor Compiler Loader Debugging tool vi (or emacs) javac hello.java java hello ...... JDK (Java Development Kit) = IDE+JRE Eclipse = IDE 5/6/2019 IT 179

ProblemsSolutions cycle Customers System analyst, Project leader Problems Senior Programmers Syntax Semantics (human) Algorithms Programmers Programs in JAVA (or any high level Programming Language) compiler Assembly IDE (computers) VM Assembler Machine code linker Results 5/6/2019 IT 179

How much effort in solving a problem After ITK 168 This is a basic requirement. We need to reduce this portion 6 month from now After ITK 179 This is more important and difficult; data structures, algorithm analysis 5/6/2019 IT 179

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…) 5/6/2019 IT 179

Robot Class name Attributes Constructor Services, methods 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() Class name Attributes Constructor Services, methods UML class diagram for Robot 5/6/2019 IT 179

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(...........) 5/6/2019 IT 179

class defined in the package Anatomy of a Java Program class defined in the package 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); } Variable declaration classes methods arguments 5/6/2019 IT 179

Task: deliver X from (1,2) to (3,1) and step away 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.turnLeft(); karel.turnLeft(); karel.pickThing(); karek.move(); karel.move(); karel.move(); karel.putThing(); } 1 2 3 4 X 1 2 3 4 named Karel 5/6/2019 IT 179

Anatomy of a Java Program 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.turnLeft(); karel.turnLeft(); karel.pickThing(); karek.move(); karel.move(); karel.move(); karel.putThing(); } 5/6/2019 IT 179

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); } 5/6/2019 IT 179

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 1992-2003 by ...... * * * **********************************************************/ 5/6/2019 IT 179

Reusing Codes Composition A class has another class, “has a” relation Inheritance A class has another class, “has a” relation A car has an engine A class inherits another class, “is a” relation An SUV is a car 5/6/2019 IT 179

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); ...... } 5/6/2019 IT 179

Composition: has a A BankAccount has a Client, has a List of BankTransaction public class BankAccount { private Client client; private List<BankTransaction> transactions; // other fields ... } 5/6/2019 IT 179

Classes: A class is a concept of something Vehicle 4 wheels, seats, engine, windows, color…… accelerate, start, stop, turn, lock, ............... Truck ………… Sedan ………… Focus ………… Matrix ………… SUV ………… 5/6/2019 IT 179

Inheritance: From membership point of view A SUV is a vehicle, but a vehicle may not be a SUV Any SUV is a Vehicle Vehicle SUV Base concept Honda Pilot Derived concept Java Object Number Base class Integer Double Derived class 5/6/2019 IT 179

Inheritance: From functionality point of view All vehicle can do, SUV can too The SUV has every properties and function of the Vehicle SUV Vehicle Derived class Base class 5/6/2019 IT 179

UML (Unified Modeling Language) Diagram Vehicle SUV Truck Sedan Honda Pilot Focus Matrix Matrix XRS 5/6/2019 IT 179

my_a is invisible to B = A - my_a: int +get_a():int B B - my_b: int +get_b():int B - my_b: int +get_a():int +get_b():int = 5/6/2019 IT 179

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. 5/6/2019 IT 179

An enhanced robot = Robot ExperimentRobot ExperimentRobot 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() An enhanced robot 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(); ExperimentRobot ExperimentRobot(City aCity, int aStreet, int anAvenue, Direction aDir) void turnAround(); void turnRight(); void move3(); = 5/6/2019 IT 179

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 5/6/2019 IT 179