CSC 142

Chapter 1: Intro to Java

Sections:

1.1 Basic computing concepts

1.2 And now, Java

1.3 Program errors

1.4 Procedural decomposition

1.5 Case study: DrawFigs

Note: the first chapter is definitions-heavy.

Section 1.1: Intro to Java

Definitions

• Algorithm
• Program
• Hardware ("Hardware: the part of the computer that you can kick")
• Software
• Digital
• Binary
• Program execution
• Compiler
• Java Virtual Machine (JVM)
• Java Runtime Environment (JRE)

Material

Things to cover:

• Java class libraries (standard library)
• Java programming environment
• Java Hello World program
• Eclipse editor ("Why can't Java programmers see well?" "Because of the Eclipse.")
• Console window/command line

Quotes

1995: Oracle: "Java: A simple, object-oriented, network-savvy, interpreted, robust, secure, architecture-netural, portable, high-performance, multithreaded, dynamic language."

Life Skills

Life skills track:

• Pay attention and FOCUS
• RTFM
• Follow directions and read carefully
• Whether it's your compiler, or your instructor, or your fellow students - pay attention to what's being said
• Skill will pay off when you start to compile your Java programs

Section 1.2: Java

Materials

Class

• Every program, all Java code, lives in a class
• Class header
• Class methods
• Statements
• String literals
• System.out.println
• Escape sequences
• print vs println

Complex example: draw figures

• ASCII diamond, X, rocket

Code comments, white space, readability:

• Comments

Profiles

• James Gosling - Oracle, tech companies, open source vs. enterprise, hackers vs suits

Section 1.3: Syntax Errors

Material

Different types of errors:

• Where the errors happen - the normal process - (code) --> (compiler) --> (bytecode)
• Errors at compiler level - syntax errors - book lists common syntax errors
• Errors at code level - bugs - errors in the logic of the program (wrong idea, or right idea but implemented wrong)

Pofiles

• Grace Hopper

Section 1.4: Procedural Decomposition

Materials

Decomposing complexity:

• Decomposition concept: split into functions, tasks, subtasks

C is very verb-oriented, action-oriented

Java is very noun-oriented, object-oriented

Procedural programming:

• Function-based, action-based programming
• How to decompose task of baking a cake
• Static methods (help serve function of.......... functions)

Object oriented programming version:

• c = new Cake(); c.make()
• Encapsulating complexity of the object
• Example in book: drawBox, drawTopX, drawBottX

Flow control

• How control changes with function calls
• Objects: with OOP it becomes more complicated to follow the flow of the program
• Procedural programs and interpreted languages: you just start at the top and go from there
• Objects: "when is this code actually used?" (have to dive in to see)
• Learning to follow program flow control
• Flow control allows you to abstract away detail
• Example runtime error

Definitions

• Decomposition
• Iterative enhancement
• Static method
• Method call
• Flow control

Life Skills

Life skills track:

• Cover non-word representations of programs

(Give them a crypto puzzle, but we haven't introduced any crypto or codes just yet)

Section 1.5 : Case Study with DrawFig

Material

Modularization of drawing program

• Breaking int pieces - not just the box, or the x, or the rocket
• but breaking down into common components, common to all parts of the program
• Take hello world program...
• Modularize it, make it reusable...

Chapter 1 Summary

Worksheet: definitions from book on one side (quiz material)

Source code for a procedural program (fizz baz foo bar buzz bam) on the other

There are N bugs, find the N bugs (self-work)

Discuss the program flow with a partner (group work)

How do we represent this program in a clear and concise way?

Transform foo bar into get ready for school - proper names can help clarify understanding

Lecture: broken up into 1.5 parts

• Broad brush-stroke over chapter 1
• Memorize definitions
• Know XYZ for quiz
• Spend a majority of time on in-class exercises
• FOCUS: KNOW HOW TO RUN/SET UP HELLO WORLD
• FOCUS: KNOW DEFINITIONS
• FOCUS: KNOW FUNCTIONS AND PROGRAM FLOW
• FOCUS: KNOW ERRORS/EXCEPTIONS

Quiz/exam/assessment material:

• Hello world, basics, public static void main, syntax
• Definitions matchup
• Functions questions
• Program flow questions
• Exceptions: spot the bug... spot logical errors... spot syntax errors...

Need to make beginnings of class difficult, to send the message that they can't let it slide

Deliverables

Intro to Java

• Know how to set up and run hello world
• How does it work, role of compliler vs editor
• JRE vs JVM vs JDK
• Public static void main
• EEverything is a class
• Filename = class name
• Correct syntax, protected keywords

Definitions

• algorithm, program, hardware/software, digital, binary, program execution, compiler, JVM, JDK, JRE, class header, class methods, statements, string literals, system.out.println, escape chars, print vs println, exception, decomposition, flow control, iterative enhancement, static method