1. Introduction to Algorithm Design
CSCI
Processing
CSCI
Introduction to Algorithm Design
An Introduction

2. Programming Languages
An abstract "human understandable" language for telling the computer what to do
The abstract language must be translated into the low level language understood by the machine

3. Programming Languages
How does a computer work?
The translation from a text source to machine code is accomplished by an interpreter or compiler
How does a compiler work?
How does an interpreter work?
Instruction 1
(moving the number from memory location "3" to Register # 1)
Instruction 2
(moving the number from memory location "4" to Register # 2)
Instruction 3
(Adding Register #1 and Register # 2, and putting the result in Register # 3)
Instruction 4
(Moving the contents of Register # 3 in Memory location "4")
A compiler is a program that processes statements written in a programming language and converts them into machine language, binary code, that a computer processor uses. E.g. Java, C, C++
An interpreter translates code one line at time, executing each line as it is translated. Generates binary code that is never compiled into one program entity, but interpreted every time the program executes. E.g. BASIC, JavaScript, Perl (can also be compiled)

4. A Simple Java Program Human Readable??
/* this is a simple Java program */
class Example {
public static void main(String args[]) {
System.out.println("this is a simple Java program"); }
Human Readable??

5. Java VM assembly code (bytecode)
Bytecode is interpreted by machine-specific Java Virtual Machines (JVMs).
Bytecode consists of simple, step-by-step instructions for the JVM.
public static void
main(java.lang.String[]);
Code:
0: iconst_0
1: istore_1
2: goto 30
5: getstatic
8: new
11: dup
12: ldc
14: invokespecial #23
17: iload_1
18: invokevirtual #27
21: invokevirtual #31 …

6. How Java Works
Source code is first written in plain text files ending with the .java extension.
Those source files are then compiled into .class files by the javac compiler. A .class file does not contain code that is native to your processor; it instead contains bytecode — the machine language of the Java Virtual Machine (Java VM).
The java launcher tool then runs your application with an instance of the Java Virtual Machine.

7. Java Virtual Machine
Java VM is available on many different operating systems.
The same .class files are capable of running on Microsoft Windows, the Solaris TM Operating System (Solaris OS), Linux, or Mac OS.
The JVM may use JIT (Just-In-Time) compilation to translate bytecode to machine language

8. But we’re using Processing
Processing is built on top of Java
Supports script-like coding
Easy to get simple programs up fast
But allows transition to full Java programming
Has built-in methods and classes to make drawing easy
Easy to export program to applet

9. Processing Environment
Menu
Toolbar (run, stop, new, open, save, export)
Tabs
Text editor (this is where you type code)
Message area (feedback, errors)
Text output (print commands)

10. Drawing in Processing
Automatic creation of display window
Window has a coordinate system for drawing

11. Let's draw a point: point()
point(x,y) – draws a point at the location x, y
Try it in Processing:
point(50, 50)
Unexpected token: null – what the !?!
Compiler errors appear in the bottom pane
All lines must be terminated with a semicolon ;
Try drawing several points

12. Important for being able to look back at your code and understand it
Comments
Comments are non-program text you put in the file to describe to others (and yourself) what you’re doing
Important for being able to look back at your code and understand it
Single-line comments begin with //
Multi-line comments begin with /* and end with */
Commenting and un-commenting lines useful for figuring out code

13. Moodle - http://learnonline.unca.edu
If you are new to Moodle, a new account was created for you and the login instructions, including your password, was ed to your UNCA  address.  If you forward your UNCA  to an external account, check the Spam/Bulk mail folder of that account for the .
If you have forgotten your password, go to the Moodle login screen and select the Lost Password link.
However, presently the Moodle section isn’t ready

14. Lab 1
Lab 1: Draw a 200 x 300 white canvas. Add 5 points and 5 lines. Revise the 5 points and 5 lines into a composition.

15. Homework 1 Read pages 1-10 for our next class.
If you have a home computer, download and install Processing from processing.org

16. Why three Java courses? “Traditional” CS1 (201.001 & 201.002)
Starts with Python
Uses drjava as IDE and interactive Java evaluator
Uses “media computation” package
Mathematical CS1 ( )
How to compute it
Use NetBeans as IDE
Closest to the traditional CS1`
Processing CS1 ( & )
Uses Processing as IDE
Uses Processing for multimedia packages
Ends with Arduino