Prof. Matthew Hertz SH 1029F / 888-2436 [email protected].

CSC 212 – DATA STRUCTURES

Prof. Matthew HertzSH 1029F / 888-2436 [email protected]

Objectives Met in CSC212

Develop solution over entire software lifecycle Implement & test computational solutions Describe which tools to use & why, given a

problem Know theoretical foundations of

computing Trace & analyze algorithms

High-level Objectives

Become programmers, not just “code monkeys” Working on your own, develop solutions

from scratch Explain your decisions and why they were

best choice Learn common real-world development

techniques

High-level Objectives

Become programmers, not just “code monkeys” Working on your own, develop solutions

from scratch Explain your decisions and why they were

best choice Learn common real-world development

techniques Master basic tools needed for all future

work Will cover topics from about 50% of GRE

subject test “Data structures critical for good

performance” Have fun

Expectations of Me

Lectures prepared and organized Give interesting, thoughtful, fun

problems Be (reasonably) available to answer questions Be honest and forthright

Why Most Classes Suck

Teaching Style

Reasoning more important than actual answer Rarely re-asked question within class or

afterward Even if correct, lucky guesses not

meaningful Explaining how & why demonstrates

mastery

Class participation is vital Need to understand problem to adjust

approach

Adult Learning

Students read material before class Answer initial questions at start of class (Short) lecture explains key ideas

Provides 2nd opportunity to see material Also will limit long, boring droning

Students work in teams to solve problems Make sure you actually understand material Easy to correct mistakes if caught at the start

Adult Learning

Expectations of You

Work hard Come to class prepared Support & help all your teammates Ask for help early and often

Let me know what you are thinking

Attendance

Attendance is mandatory Talk to me when you know you must miss

class You are responsible for every class Missing class is never acceptable excuse

Best way to earn a poor grade: skip class

Deadlines

Have 2 virtual “extensions” Each used to get 1 day extension on

assignment Can use both on single assignment for 48-hour

delay Late work not accepted without extension

If you know you cannot make a deadline, talk to me

Earlier we talk, the better the chance solution possible

Grading Philosophy

Grades reflect student's demonstrated ability Not a competition where grades are

relative I will quite happily give A to entire class, if

all earn it A not automatic just because score is

highest in class Remain fair for students past, present,

& future When in doubt, I consider what most

equitable Hard work alone insufficient to raise a

score Working efficiently important life skill to be

rewarded

Grading Philosophy

Doctor Who Cures You

Doctor Who Works Hard

Would you rather have:

Course Grading

Midterms 24%Final 25%

Quizzes 10%Projects 18%

Weekly Assignments 11%Daily Activities 6%

Templates 6%

Grades available via Angel Midterms given on Oct. 1st & Oct.

31st

3 programming projects during semester

Course Grading Goals

Learn & build skills used by “real” programmers

Develop understanding needed for future work

Catch and correct problems early Many ways presenting material during

the term Increases chances that all students can

“get it”

Course Grading Goals

Learn & build skills used by “real” programmers

Develop understanding needed for future work

Catch and correct problems early Many ways presenting material during

the term Increases chances that all students can

“get it”

I am mean & like watching students suffer

Weekly Assignments

Posted on Angel each week Usually due by 5PM following Tuesday

Virtual extensions okay to use on all but first one

Before submitting, ask me questions you still have

Several goals for these assignments Provide additional programming

opportunities Reinforce material from each lecture

Questions should seem easy & take under 10 min. Means you are doing well

Templates

Take notes on readings’ important details Main Angel page links to templates you must

use Notes written by classmates so easier to use Each template is due before lecture topic is

discussed (Don’t care where you get information from)

Use notebooks during labs & tests Without notebook, no answers to

related questions Can also use book, but book less useful than

good notes Write 2, but get whole set; notes handed out

to class

PowerPoint Slides

Students need to take notes on their own Writing increases odds of remembering

ideas Really, really bad idea to not take notes

Trapped me into specific way of lecturing Limited opportunities to use clever memory

tools Lectures often resembled

Students During Lecture

Workings of My Slides

Slides contain many pictures, little text Lectures interesting & fun (or at least better) Provides you with good way to reinforce

lessons

Will suck as actual notes Print handout & take notes on the side Write down what the steps animated on the

slide Slides (with notes) actually usable on tests,

labs, class…

Collaboration

Fellow students are a great resource Provides multiple viewpoints &

understandings Get together, discuss material, and

study Can have them answer lingering questions Clarify assignment and what it requires Learn and practice some basic social skills

Collaboration

Work you submit must be done by you When discussing homework or projects

Leave conversation with memories only Wait 15+ minutes before starting on your

own Solutions always unique after waiting

Once started, each student should work alone

STEP AWAY FROM COMPUTER then talk code

Collaboration

Work you submit must be done by you When discussing homework or projects

Leave conversation with memories only Wait 15+ minutes before starting on your

own Solutions always unique after waiting

Once started, each student should work alone

STEP AWAY FROM COMPUTER then talk code

When in doubt, ask me

Coding Help

Will work on testing & debugging skills To get debugging help in CSC212

Method(s) must be commented (javadoc) Must use a trace or similar to look for bug

Students find own solution once they start doing this

If problem not fixed, gives us starting point to work

Learn to fix your own errors & not rely on the Professor

Textbooks

Goodrich & Tamassia , Data Structures and Algorithms in Java, 5th Edition, Wiley, 2010.

Readings from book listed as "GT" in schedule

Available at bookstore & online (Amazon, etc.)

Will cover about 50% of the textbook CSC213 looks at other half of the book

Only new textbook for the year

Textbooks

Readings listed as “Horstmann" in schedule

Textbook from CSC111 last Spring Early in term used to review CSC111

concepts Few Java concepts introduced as we go

along, also But this is your choice, new concepts also

in textbook

Course Website

Pages for course found on Angel Handouts, slides, assignments posted

before class Can also find solutions after work is due

May not include everything said in class Better than nothing, but worse than

being here!

Ever Have A Bug?

At some point, everyone must fix bug in code What should you do first after discovering

the bug?

Ever Have A Bug?

At some point, everyone must fix bug in code What should you do first second after

discovering it?

Fixing Bugs

Three common ways students fix bugs: Guess where error is and make random

change Use Eclipse debugger to run program & find

source Get out your pencil & paper and draw a

memory trace

Normal Method of Debugging

Also called "debugging-via-drunken-walk" Can work for SMALL programs with limited

choices Guessing for millions of lines of code harder

Not at all effective at actually fixing errors Entire point is to avoid understanding bug's

cause "Fix" may cause other errors later on in

program Cannot prevent future errors using this

approach

Better Method of Debugging

Could use Eclipse debugger to find and fix bug Set breakpoints to stop program where bug

likely Use step filters to walk through the

program bit by bit Spend a few hours learning how to make it

work Can get to root of problem once it is

executed But requires executing entire program to

trigger bug Cannot work backward to try and

understand why

Best Method of Debugging

Generating memory trace has many benefits Could check algorithm – don’t need any

code to try Can make up situations and just trace a

method Look back through trace to see root cause

of bug Trace code by running it like you were

computer DON’T SKIP STEPS – easy to (wrongly)

assume things As you go along update variables’ values

GIGO effects limit tracing’s effectiveness

Benefits of Heap Traces

Draw what actually occurs in memory Pictures used to debug rather than bare

text Much easier to understand what a method

does Excellent way to learn new programming

topics Scientific studies found improves

student grades Debugging time decreased greatly at same

time Greater support for these traces in

Eclipse Drawing of static trace integrated with

debugger Over this term should see tools improve

Starting a Heap Trace

Paper holds 2+1 areas separated by vertical lines Program stack drawn on one side of page Other side of page holds the program heap (Program output shown on page as well)

Objects allocated during run drawn in the heap Will discuss how this is done next week

Draw frame on top of stack each method call Fancy name for box labeled with method

name All parameters & local variables added

within box

Data Types

8+1 primitive data types Examples: boolean, byte, char, int, double, String*

Only types that work with Java operators Operators include: +, -, %, &&, ||, >=, <, !

Primitives used natively by computers Means using them is very quick Implies greater support within the language

Primitive Types

Primitive variables are simple to use Each variable is “xerox” holding a value

Assignment copies value Update assigned variable only; changes not

reflected

Starting a Heap Trace

public static void main(String[] args) {String s = “”;for (int i = 0; i < 5; i+=2) { s = s + i; System.out.println(s);}

}

Announcements

Interested in joining programming team? Register for CSC299 (0-credit course) & learn more! Relaxed & ungraded “class” meets Thurs. 4:30 – 5:30

CSC tutoring center starting to ramp up Starting next week (or so) tutors available in SH1029G May have limited openings if you know HTML or C++

Consider getting flash drive to hold coursework Life much easier to use single workspace for year

For Next Lecture

Mourn summer’s end & start of homework

Weekly assignment problems start today For 1st week of classes, will be due before each

lecture Help you review your Java and get rust out of

system

There is reading for Wednesday From Horstmann or course’s text (pick one to

use) Chapters listed on Angel & in syllabus

Prof. Matthew Hertz SH 1029F / 888-2436 [email protected].

Documents

Transcript of Prof. Matthew Hertz SH 1029F / 888-2436 [email protected].