Software Construction - TU/ewstomv/edu/sc-hse/downloads/Series_01/slides_01.pdf · Imperative core of the Java programming language Study material c 2014, T. Verhoe @ TUE.NL 4/28

Lecture 1: Introduction

Software Construction

in Java for HSE Moscow

Tom Verhoeff

Eindhoven University of Technology

Department of Mathematics & Computer Science

Software Engineering & Technology Group

www.win.tue.nl/˜wstomv/edu/sc-hse

c© 2014, T. Verhoeff @ TUE.NL 1/28 Software Construction: Lecture 1

About the Lectures

• In English

– Slow me down, if it goes too fast

– Interrupt me, if it is not clear

• Audio/Video link has limitations

• Slides, tool demo

• Not enough time to explain all details in lecture:

You must explore yourself


About the Lecturer

• Study: Applied Mathematics

• PhD Thesis: A Theory of Delay-Insensitive Systems

• Running: long-distance

• Music: recorder (wooden flute) quartet

• Mathematical Art (with my father)

• Teach math enrichment in a primary school

• Teach/Research at TU/e: Model-Driven Engineering


Overview

• Introductory problem

• Organizational issues, the big picture

• Motivation, background

• Imperative core of the Java programming language

• Study material


Introductory Problem

• What is a problem?


Introductory Problem

• Problem =

Difference between

what you want and

what you have


Dice Game: What We Want

• 5 players , 2 cubic dice , each producing values 1 through 6

• Per round , each player rolls the 2 dice

• Player with unique highest roll wins round; otherwise, no winner

Player Result

1 2 3 4 5

3 8 7 10 8 Player 4 wins

6 11 4 8 11 no winner

12 12 13 12 12 ?

• Player 1 requests to roll a single dodecahedron , whose faces arenumbered 1 through 12

• Question: How does this influence the game?


Solving a Problem through a Program: What We Have

What you have:

• Programming language

• Programming tools

• Programming techniques

What you do:

• Analyze the problem

• Design a program (text)

• Run the program, provide input, use output


Weekly Schedule

Course: 2 × 7 weeks

Day Moscow Time What

Monday 16:40 – 18:00 Lecture

Monday 18:00 – 18:30 Question & Answer

(if schedule permits it)

Thursday 23:00 Homework deadline


Homework

• We use peach3 at ext.peach3.nl

• Register

Username = initial + family name; e.g. sshershakov

• Join course Software Construction for HSE (2014–2015)

• Submit your work

• Receive feedback

– from peach3, automatically

– from me or HSE assistants

– from your peers (peer review)


Study Material

• [DE] Introduction to Programming Using Java

by David Eck, Version 7.0, August 2014

• [EB] Programming in the Large with Design Patterns

by Eddie Burris, Pretty Print Press, 2012

• Slides, handouts, example code, assignments

• Miscellaneous (web) resources

• Frequently Asked Questions

• Subversion repository (see FAQ)


Additional Study Material

• The Java Language Specification

by James Gosling et al.


Tools

JDK Java Development Kit, Java 7 Standard Edition

DrJava IDE with Interactions

NetBeans IDE with GUI designer, and plug-ins

Javadoc Java documentation tool

JUnit Java Unit Testing Framework

JaCoCo Java Code Coverage plug-in

UML Unified Modeling Language

SQE Software Quality Environment

Profiler Performance Analysis


Motivation

• Assumption: You have some programming experience

Syntax, semantics, pragmatics (conventions)

Types, variables, expressions, statements, input/output

• Goal: Systematic design of larger object-oriented Java programs

• Design: Blueprint; also: activity leading to blueprint

• Concepts, terminology, notation

How to communicate about programs and about programming

• Rational design

How to reason about programs, how to motivate design decisions


Product, Process, and Documentation

Product: machine-executable ‘working’ program or component

Product documentation: artifacts to support product (design)

Process: the way persons work (individually, or as a team)

Guidelines, step-by-step check lists, design methods, . . .

Process documentation: describes/prescribes a process

Focus on: methodical process, producing documented product

Not on product itself; not on creation of process documentation


Quick Intro to Imperative Core of Java

• Chapters 2, 3, and 7 of book by David Eck

• Comments: /*... */ /** ... */ //...

• Types, Values, Literals: int long boolean String double

• Expressions: (1 + 2) * 3 == 9 "ab"+ "c"

• Variables, Assignment Statements: variable = expression;

• Statement Blocks: { ... }

• Control Statements: if else, while, for

• Console Output: System.out.println(...);

• Arrays: int[] a = { 0, 1, 2 }; ... a[expression] ...


How to Practice with Java

Install DrJava and do some Interactions

> 2+2

4

> import javax.swing.JFrame;

> JFrame jf = new JFrame(); // no window visible

> jf.show(); // now locate the window on your computer screen

> jf.getWidth()

128

> jf.setSize(640, 480);

> jf.setTitle("Hello, here I am!");


What Is a Java Program?

• At compile time: Collection of classes ,

where each class has

– typed variables , also known as fields or attributes or

member variables

– methods , optionally with typed return value and parameters

• At run time: also a collection of objects ,

where each object is instantiated from a class,

and each variable in an object has a value from its type


Java Programs in Week 1

• One class

– without variables, but with constant definitions:

final static Type NAME = expression;

– one (static) method

with parameters (input) and a return value (output)

• No objects


Simple Java Program

1 public class EchoArgs {

2

3 public static void main(String[] args) {

4 for (String arg : args) {

5 System.out.println(’"’ + arg + ’"’);

6 }

7 }

8 }

In DrJava Interactions: run EchoArgs Hello HSE! produces

"Hello"

"HSE!"


Important Notes

In Java, a class named Xyz must be stored in a file named Xyz.java

In Java, by default, execution starts at public static void main

which must have one string array parameter String[] args

In DrJava, this main is invoked by run ...

In DrJava, static method m of class C is invokved by C.m(...)


Program for Dividing Candy

1 /**2 * k kids together receive c candies.

3 * They wonder whether it is possible

4 * to divide all candies fairly.

5 *6 * If this is possible, they also want to know

7 * how many candies each of them gets.

8 * This is a number q such that c == q * k .

9 *10 * k, c, and q are non-negative integers, less than 10ˆ18.

11 *



1 

2 Replace this line

3 

4 */

5 // -----8<----- cut line -----8<-----



1 public class Candy {2

3 /**4 * Returns a negative value to indicate5 * that the division is impossible, and otherwise,6 * returns the number of candies each kid gets.7 */8 static long divide(long k, long c) {9 long result; // value to be returned

10 // put your solution here11 result = 5; // just some value to make it compile12 return result;13 }14 }

In DrJava Interactions: Candy.divide(3, 15) produces 5


Important Constraints

• Put in your name, group, and the date, above cut line with --8<--

• This week

– only one static method; no auxiliary methods, no objects

– no package statements

– no import statements

• Write readable code (see Coding Standard)

• Test your program before submitting (Quality Assurance)

• Submit your own work (individual assignments)


Program for Dice Game

1 /**2 * Consider the following dice game.

3 * Five players each roll once per round.

4 * Player 1 rolls a (fair) dodecahedron,

5 * having 12 faces with the numbers 1 through 12.

6 * The other players (2 through 5) roll two fair dice,

7 * each having 6 faces with the numbers 1 through 6.

8 * The player with the unique highest roll

9 * wins the round. If the highest roll is

10 * not unique, then there is no round winner.

11 *



1 

2 Replace this line

3 

4 */

5 // -----8<----- cut line -----8<-----



1 public class DiceGame {

2

3 /** Number of players, >= 1 */

4 final static int NUM_PLAYERS = 5;

5

6 /** Index for frequency of rounds without winner */

7 final static int NO_WINNER = 0;



1 /**2 * Simulates r >= 0 rounds of the dice game and

3 * returns how often each player won.

4 * The return value is an array, where

5 * index 0 counts the number rounds without winner, and

6 * index i > 0 counts the number of rounds won by player i.

7 */

8 static public int[] simulate(int r) {



1 static public int[] simulate(int r) {

2 int[] result; // winning frequencies

3 result = new int[1 + NUM_PLAYERS]; // initialize to 0

4 //# BEGIN TODO: Provide your solution

5 // Replace this line

6 //# END TODO

7 return result;

8 }

9

10 }


More Practicing

• codingbat.com


How to Write Readable Java Source Code

• Code Conventions for the Java Programming Language

• Java Coding Standards by ESA BSSC (2005)

• Concerns: layout, naming, commenting, structure


Coding Standard for 2IPC0

10 simple conventions

Layout:

• NetBeans > Source > Format : default settings do a good job

• Declare no more than one field or local variable per line

Comments:

• Each public class, constructor, method, field has doc comment

• Each non-public class, constructor, method, field, local variable

has normal (non-doc) comment


Summary

• Consult the course page: www.win.tue.nl/˜wstomv/edu/sc-hse/

• Study Material

• Imperative Core of Java

• DrJava, codingbat.com

• Register in peach3: ext.peach3.nl

• Assignments: Candy, DiceGame

Documents

Software Construction - TU/ewstomv/edu/sc-hse/downloads/Series_01/slides_01.pdf · Imperative core of the Java programming language Study material c 2014, T. Verhoe @ TUE.NL 4/28