CMSC 131 Fall 2008: Object-Oriented Programming I Course Overview and Instructions - Prof., Study notes of Computer Science

Download CMSC 131 Fall 2008: Object-Oriented Programming I Course Overview and Instructions - Prof. and more Study notes Computer Science in PDF only on Docsity! 1 CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) CMSC131 Lecture Set 1: Introduction Topics in this set: 1. Course information 2. Tools needed for this course 3. Computer terminology basics 1CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) CMSC 131
Name: “Object-Oriented Programming I”
Instructor: Jan Plane
Class meetings
Lecture sections
6 lecture sections
2 instructors
Lab sections
11 lab sections
10 teaching assistants 2 2CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Coordination of Sections
Six sections total of CMSC 131
3 lectures taught by me
other 3 lectures taught by Fawzi Emad
Ten TAs in total for the sections
All sections will be closely coordinated:
Same lecture material on same day
Same projects
Same labs
Coordinated exams
Lab/Discussion/Recitation Sections
exercises – laptops
quizzes
new material occasionally 3CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) What Is This Course?
A fast-paced introduction to techniques for writing computer programs!
Skill Development in Programming
Conceptual Understanding of Programming
Not really “computer science”
There will be quite a bit of work but assumes you are starting at level 0.
Keys to success
Attend all classes and lab sections
Start assignments early – and continue until you truly understand
Get help early if you are having trouble – 2 instructors & 10 TAs
Study every day
it doesn’t work to cram for these exams
ask questions as soon as you realize you are confused
Check announcements on course web-page every day 5 8CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Basics of Eclipse
http://www.cs.umd.edu/eclipse/EclipseTutorial/
Eclipse is used to:
Create
Edit
Compile
Run
Debug programs (for this class, Java programs). 9CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Basics of Eclipse-speak
Project: collection of related source files To create a program in Eclipse:
Create a new project
Create files in the project
Perspective: framework for viewing and/or manipulating programs
Important perspectives in this class:
Java: for creating, running programs
Debug: for tracing, removing errors in programs
CVS repository: for interacting with assignment-submission system 6 10CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Eclipse Demo 11CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Class Projects with CVS
You will use Eclipse for Java programming in this course
How will you:
obtain (check-out) files that are supplied to you
save (commit) the files for later work
turn in (submit) when you are finished class projects?
CVS (= Concurrent Versions System)
Tool for project-file management
Maintains versions, etc.
Allows different sites to work on same project 7 12CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) CVS Worldview Files in “repository” Server Files (local copies) Client 1 Files (local copies) Client 2 “checkout” “checkout” “commit” “commit” 13CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) CVS in More Detail
CVS server maintains current versions of files in project (= “repository”)
To access files from another machine (“client”), repository files must be “checked out”
Changes to files on client may be “committed” to server, with changed files becoming new version
(Once a repository is checked out by a client, subsequent versions may be accessed via “update”) 10 18CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) To Checkout a Project (cont.) 1. Open repository name, then “Head” 2. Right-click on project name to save 19CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) 11 20CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Working on Project
When you switch back to “Java” perspective, your project is now there!
When you save in “Java” perspective, changes are automatically committed to CVS repository. 21CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Submitting the Project
Edit the file
Make sure it runs correctly
Submit the project for grading
Go to submit.cs.umd.edu to see test results
Public tests
Private tests
Release tests
give limited feedback (first two failed tests give more)
costs you “tokens” – usually 3 to start with
spent tokens regenerate in 24 hours 12 22CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Study Questions
Login: study
Password: daily 23CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Computer Organization
Hardware: physical parts of computer
Monitor, mouse, keyboard
Chips, boards
Cables, cards
etc.
Software: non-physical (“logical”) parts of computer
Programs = instructions for computer to perform 15 28CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) How Are Characters, Etc., Represented? Via encoding schemes Example: ASCII (American Standard Code for Information Interchange)
Standard for encoding character values as bytes
In ASCII:
‘A’ 01000001
‘a’ 01100001
‘,’ 00101100
etc. There are other character encoding schemes also: Shift-JIS, Unicode, etc. 29CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Software Overview 1. Operating system: manages computer's resources; typically runs as soon as computer is turned on. Typical responsibilities:
Process management Determines when, how programs will run on CPU time
Memory management Controls access to main
I/O, window system, network control Performs low-level drawing, communication operations
Security Manages user IDs, passwords, file protections, etc. 2. Applications: programs users interact directly with; usually are explicitly run. Examples:
Word processors
Games
Spreadsheets
Music software,
Etc 16 30CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) How Programs Are Executed foo.exe Program “foo” initially stored in secondary storage COPY Program copied into main memory CPU CPU executes program instruction- by-instruction 31CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Programming Languages
Used to write programs that run on computers
Generations of programming languages
1st (1GL): machine code
2nd (2GL): assembly code
3rd (3GL): procedural languages
4th (4GL): application-specific languages
5th (5GL): constraint languages 17 32CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) 1st Generation: Machine Code
Recall: computer data is 0’s and 1’s.
In machine code, so are programs!
Program: sequence of instructions
Machine code: instructions consist of 0’s and 1’s
Next slide: example machine code instruction from MIPS (= “Microprocessor without interlocked pipeline stages”) architecture
Popular in mid-, late 90s
Instructions are 4 bytes long 33CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Example MIPS Instruction
“Add data in addresses 1, 2, store result in address 6”: 00000000001000100011000000100000
??? 000000 00001 00010 00110 00000 100000 opcode 1st address 2nd address destination address shift amount function specifier 20 38CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Compilers
Computers can only execute machine code
Compilers are programs for translating 3GL programs (“source code”) into assembler / machine code source compiler asm 39CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Interpreters
Another way to execute 3GL programs
Interpreters take source code as input
Interpreters execute source directly
Much slower than compiled programs
Debuggers are based on interpreters
Debuggers support step-by-step execution of source code
Internal behavior of program can be closely inspected 21 40CMSC 131 Fall 2008 Jan Plane (adapted from Bonnie Dorr) Object Oriented Terminology
Procedural Languages
have procedures that can be reused
Object Oriented Languages
centered on the objects
object
principal entities that are manipulated by the program (nouns)
class
a “blueprint” that defines the structure for one or more objects
method
java term for a “function”, a “procedure” or a “subroutine”
this is the code that does something (verbs)
main method
a special method that defines where program execution begins
statements
individual instructions