Jens Dalsgaard Nielsen Jan Dimon Bendtsen Dept. of Electronic Systems Basic Programming INS-basis GF, PDP and HST

Course Goals To understand the activity of programming To become familiar with computing environments, compilers etc. To be able to program, compile and run Java programs To be able to recognize (and fix) syntax and logic errors To be able to use computer programs as an engineering tool

Prerequisites Computer savvy (file management, text editing) Problem solving skills Time management High school math (algebra, trigonometry) No prior programming background required

Course Organization Introduction to the course, getting started Tools, getting operational Classes and objects Program control Basic GUI programming Data structures File I/O Slightly less basic GUI programming 1)+10) Mini-project

Examination “Mini-project” - at the end of the course, you write a program that:  Satisfies a “requirement specification” posed by the lecturers  Demonstrates that you know how to program in Java  Demonstrates that you are able to use an Integrated Development Environment (Eclipse) Individual examination (but it is OK to do the actual work in small groups)‏

Chapter 1 Introduction to Java Programming

What Is Programming? Computers are programmed to perform tasks Different tasks = different programs Program  Sequence of basic operations executed in succession  Contains instruction sequences for all tasks it can execute Sophisticated programs require teams of highly skilled programmers and other professionals

Schematic Diagram of a Computer Figure 5: Schematic Diagram of a Computer

The Java Programming Language Simple Safe Platform-independent ("write once, run anywhere") Rich library (packages) Designed for the internet

An Integrated Development Environment Figure 9: An Integrated Development Environment

File HelloTester.java 1: public class HelloTester 2: { 3: public static void main(String[] args) 4: { 5: // Display a greeting in the console window 6: 7: System.out.println("Hello, World!"); 8: } 9: } Output Hello, World!

HelloTester in an IDE Figure 12: Running the HelloTester Program in an Integrated Development Environment

A Simple Program Figure 13: Calling a Method System Class System.out Object println Method public class ClassName public static void main(String[] args) // comment Method call

Syntax 1.1: Method Call object.methodName(parameters)‏ Example: System.out.println("Hello, Dave!"); Purpose: To invoke a method of an object and supply any additional parameters

Errors Syntax errors Detected by the compiler Logic errors Detected (hopefully) through testing System.ouch.print("..."); System.out.print("Hello); System.out.print("Hell");

The Compilation Process Figure 14: From Source Code to Running Program

Chapter 2 Using Objects

Types and Variables Every value has a type Variable declaration examples: Variables  Store values  Can be used in place of the objects they store String greeting = "Hello, World!"; PrintStream printer = System.out; int luckyNumber = 13;

Types and Variables Every value has a type Variable declaration examples: Variables  Store values  Can be used in place of the objects they store String greeting = "Hello, World!"; PrintStream printer = System.out; int luckyNumber = 13;

Syntax 2.1: Variable Definition typeName variableName = value; or typeName variableName; Example: String greeting = "Hello, Dave!"; Purpose: To define a new variable of a particular type and optionally supply an initial value

Identifiers Identifier: name of a variable, method, or class Rules for identifiers in Java:  Can be made up of letters, digits, and the underscore (_) character  Cannot start with a digit  Cannot use other symbols such as ? or %  Spaces are not permitted inside identifiers  You cannot use reserved words  They are case sensitive Continued…

The Assignment Operator Assignment operator: = Not used as a statement about equality Used to change the value of a variable int luckyNumber = 13; luckyNumber = 12; Figure 1: Assigning a New Value to a Variable

Uninitialized Variables Error: Figure 2: An Uninitialized Object Variable int luckyNumber; System.out.println(luckyNumber); // ERROR - uninitialized variable

Syntax 2.2: Assignment variableName = value; Example: luckyNumber = 12; Purpose: To assign a new value to a previously defined variable.

Summary  Main goal: Programming as an Engineering tool  Examination: Mini-project  Organization: Short(?) lectures and plenty of programming at the PC  Programming exercises are carried out in Eclipse  “Hello World”  Variables are used for storing values, via assignment; they are referred to using identifiers (names)‏