Chapter 1

Introduction

Chapter Goals

To understand the activity of programming
To learn about the architecture of computers
To learn about machine code and high level programming languages
To become familiar with your computing environment and your compiler
To compile and run your first Java program
To recognize syntax and logic errors

Prerequisites

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

What is a computer?

Central processing unit
Memory
Peripherals
Executes very simple instructions
Executes instructions very rapidly
General purpose device
Programs describe specific actions

Central Processing Unit

Schematic Diagram of a Computer

Programming Languages

Machine/Virtual Machine
21 40 16 100 163 240
Assembler
iload intRate bipush 100 if_icmpgt intError
High-level language
if (intRate > 100) . . .

The Java Programming Language

Simple
Safe
Platform-independent ("write once, run anywhere")
Rich library
Designed for the internet

Applets on a Web Page

Becoming Familiar with your Computer

Login
Locate the Java compiler
Understand files and folders
Write a simple program (later)
Save your work

A Shell Window

An Integrated Development Environment

File Hello.java

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

A simple program

public class ClassName
public static void main(String[] args)
// comment
Method call
object.methodName(parameters)
System class
System.out object
println method

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

Compiling and Running

Type program into text editor
Save
Open command shell
Compile into byte codes
javac Hello.java
Execute byte codes
java Hello

From Source Code to Running Program

Errors

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

Chapter 1

Introduction

Chapter Goals

Prerequisites

What is a computer?

Central Processing Unit

Schematic Diagram of a Computer

Programming Languages

The Java Programming Language

Applets on a Web Page

Becoming Familiar with your Computer

A Shell Window

An Integrated Development Environment

File Hello.java

A simple program

Syntax 1.1: Method Call

Example:

Purpose:

Compiling and Running

From Source Code to Running Program

Errors

The Edit-Compile-Test Loop