cs61b lecture 1 beginning day 1

7/25/2019 Cs61b Lecture 1 Beginning Day 1

1/51

A Note for those Stumbling on these Slides (Hi!)

These lecture slides are not intended as written reference mate

Just reading them probably wont be very educational.

Best used in combination with webcasts and source code refere

See (Video) and (Code) links under each lecture: http://cs6
http://cs61b.ug/sp16


2/51

CS61B, Spring 2016

Lecture 1:

Introduction Course Logistics

Hello World


3/51

61B Overview

What is 61B about?

Efficiency

Algorithms. Data Structures.

Programming (efficiently)

Designing, building, testing, and debugging large programs

Use of programming tools. git, IntelliJ, JUnit, and various command line tools.

Java (not the focus of the course!)


4/51

Why study algorithms and data structures?

Daily life is supported by them.


5/51


Major driver of current progress of our civilization.
http://www.youtube.com/watch?v=8XQlIvlWqpohttp://www.youtube.com/watch?v=8XQlIvlWqpohttp://www.youtube.com/watch?v=8XQlIvlWqpo


6/51


Major driver of current progress of our civilization.


7/51


To become a better programmer.

The difference between a bad programmer and a goodwhether [the programmer] considers code or data str

more important. Bad programmers worry about the code

programmers worry about data structures and

relationships. - Linus Torvalds (Creator of Linux)


8/51


For intellectual stimulation:

Possible to draw without picking up pencilor going back over any lines.


9/51


To understand the universe:
http://www.youtube.com/watch?v=-ZcEDqyMbFwhttp://www.youtube.com/watch?v=-ZcEDqyMbFwhttp://www.youtube.com/watch?v=-ZcEDqyMbFw


10/51


To

create

beautifulthings.
http://www.youtube.com/watch?v=BIjj3Qcmbf4http://www.youtube.com/watch?v=BIjj3Qcmbf4


11/51

Everyone else is doing it, so why shouldnt we?



12/51

Who are you?


13/51

Who are we?

Instructor: Josh Hug (me) [email protected] 779 Soda

GSIs:

Leo Colobong Jimmy Lee Sarah Kim Kay Ou

Akhil Batra Alan Yao Allen Guo Allen Z

Alice Sheng Amit Vijay Akula Austin Le Anush

Carlos Flores Chris Jeng Daniel Nguyen Daniel

Dennis Zhao Gilbert Ghang Giulio Zhou Jim ReJimmy Lee Kay Ousterhout Leo Colobong Luise V

Nick Rose Ross Teixeira Rudy Laprade Sarah

Sean Zhu Sherdil Niyaz Ye Seon Lee

http://cs61b.ug/sp16/staff.html
mailto:[email protected]://cs61b.ug/sp16/staff.htmlmailto:[email protected]


14/51

But Thats Not All...

Tutors:

Colbert Guan Hayden Sheung Kuriakose "Sony" Th

Tara Rezvani Jennifer Liang Raymond ZhaoBhuvana Bellala Megan Zhu Mitas Ray

Jared Rulison Michael Aboody Laura Harker

Maurice Lee Dasheng Chen Matthew Mussome

Daniel Khasanov Khalid Shakur Raquel Layug

Julian Early Yue Andy Zhang (And more coming



15/51

But Wait, Theres More...

Lab Assistants:

Vinay Koshy Kevin Lin Lance Xing Chen Gong Evan Sheng

Mark Sun Brandon Huang Divyansh Agarwal Steven Chen Milan Saxena

Hung Vu Vy Ly Rami Shahatit Robert Matych Thong Dinh

Joyce Luong Nicolas Zoghb Seunghwna Choi Christine Munar Santos Tobar

Ruihan Zhao Anusha Syed Abhinav K Adduri Andrew Linxie Lisa Jian

Melis Kirikoglu Joe Kuang Allen Melody Huang Lily Lin

Yuxi Chen Ricardo Herrera Yuki Mizuno Yao Ge Keeyune Cho

David Zhang Parsa Khajeh Ahmad Attari Alice Tarng Antares Chen

Michelle Ahn Kevin Kim Brian Lee Stella Tao Kevin Skorstad

Patty Long Yanhe Chen Ryan Lee Andrew Dildy William Guss

Mathew Joseph Samuel Choi Andrew Leong Levon Korganyan Sagang Wee

Jonathan Ngan Kevin Li Scott Post Konrad Matthaei Aidan Clark

Jung Yun Rhee Helen Che Caroline Kim Samuel Khano Alexander Hwa

David Fang Kimberly Tze


16/51

The Manner in Which Learning Occurs (TMW
http://www.youtube.com/watch?v=OVtnnIifaU8http://www.youtube.com/watch?v=12lSScKSx20http://www.youtube.com/watch?v=12lSScKSx20http://www.youtube.com/watch?v=OVtnnIifaU8


17/51

TMWLO: A Small Minority

Lectures

Introduction to new material.

Reading

More thorough introduction.


18/51

TMWLO: The Vast Majority

Labs, Weekly(ish) Homework, and Your Own Experimentation

Practice with tools, programming techniques, Java syntax, and a

and data structures.

Section

Practice with concepts and Java syntax.

Projects

Similar to labs and HW, but larger and include a design compon


19/51

Course Logistics

This slide is green

its easy to find wheyoure looking atwebcasts.

l f i


20/51

Places to Get Information

Official Course Resources

Course website: http://cs61b.ug/sp16

Lectures (or webcasts). Piazza: http://piazza.com/class/61b

Office hours (in 779 Soda this week, somewhere else next week

Lab (ok to discuss anything, even not on lab).

Discussion.

Homework Parties.

Guerrilla Sections.

Group Tutoring Sections.

Textbook: Head First Java (optional, silly, useful).

Unofficial: Google, Stack Overflow, other programming courses on t

various online documentation, etc.

L i i l D il
http://cs61b.ug/sp16http://piazza.com/class/61bhttp://cs61b.ug/sp16


21/51

Logistical Details

For waitlisted folks: If you do project 0, I will get you in by week

If possible, go to your assigned section and lab this week.

If you dont have one yet, go to any section or lab.

If room is too full, priority goes to those officially registered Please wait outside until 2 minutes before start (XX:08).

Once attendance settles, doesnt matter which lab/section/lect

registered for.

Please post administrative issues to Piazza or send an email to

eecs.berkeley.edu

Please dont email me directly (sorry!).

1200 students * 1 minute/student = 20 hours.

61B 2 0 C St t


22/51

61B 2.0 - Course Structure

Phase 1: Programming Intensive Introduction to Java.

Weeks 1-4

One browser-based programming HW (this HW0 is optional). Three labs to introduce you to various tools (starting this week)

Two projects (proj0 and proj1).

Phase 2: Advanced Programming

Weeks 5-7 One small HW.

One large project, due 3/7.

Labs to support large project.

61B 2 0 C St t


23/51

61B 2.0 - Course Structure

Phase 3: Data Structures and Algorithms

Weeks 8-14

Labs: Implement a data structure or algorithm. Six HWs: Apply a data structure or algorithm.

One medium sized data structure/algorithms project.

See calendar at http://cs61b.ug/sp16for more.

Lab Logistics
http://cs61b.ug/sp16http://cs61b.ug/sp16


24/51

Lab Logistics

OK to work on labs ahead of time.

Lab always due by Friday at 10:00 PM.

10% of lab grade is attendance.

Dont like attending? Can instead submit early by 10:00 PM

Full credit for reasonable effort.

Some labs are freebies (automatic credit, even if you dont

14 total labs, worth 2 points each. Lowest two are dropped. No exte

grace hoursexcept emergencies.

HWs


25/51

HWs

Homework breakdown:

HW0: Optional browser based Java exercises.

HW1: Practice with advanced Java features.

HW2-7: Applications of various data structures and algorithms.

Due dates vary. See calendar.

7 total required homeworks, worth 10 points each. Lowest homewo

dropped. No extensions or grace hoursexcept emergencies.

Projects


26/51

Projects

Four projects

One lightweight project, two medium projects, one large projec

Project 0 (team): 10 points

Project 1 (team): 25 points

Project 2 (solo): 40 points

Project 3 (solo): 25 points

Project 2 will be the Hilfinger style systems project (very time in

All code on solo projects must be your own work.

Ok to discuss with others and help debug.

May have opportunities for extra credit on some projects. More late

Exams


27/51

Exams

Exams will be hard

Median scores will be lower than you might be used to (ideally

Two midterms in evenings, one final exam.

One sheet of paper (front and back) per exam.

If your midterm grades are statistically much worse than your fi

replace your midterm grade. See course info (tomorrow) for the

Exam dates (midterms tentative until room deadlines confirmed): Midterm 1: February 12th, 7:00 - 9:00 PM (drop deadline is Feb

Midterm 2: March 31st, 6:00 - 8:00 PM

May 11th(final exam) at 7 PM.

Some alternate exam times will be available.

Course Grade


28/51

Course Grade

Breakdown: 384 points total.

Midterms: 100 points total.

Final: 100 points.

Projects: 100 regular points.

HW: 60 points (10 points each)

Lab: 24 points (2 points each)

Grades are not curved, i.e. they are not based on your relative perfoSp2015, I did not change the bins at all. Tentativebins:

>323: A-

>265: B-

>207: C-

See course handout (online) for full details.

Plus occasiona

for extra credit fcourse feedbac

Course Pacing


29/51

Course Pacing

We will start off very fast.

Optional HW0 is out.

Intro to Java syntax.

Will take 1-4 hours.

Work with friends!

Recommended that you complete before your lab.

Strongly recommended that you complete by lecture Friday

Lab 1 and Lab 1B are both available.

Lab1: How to use various tools. Lab1b: How to set up your home computer (maybe do befo

Project 0 released Friday. Due next Friday Jan 29th (10 days from

semester).

Exercises all the basic Java features.

Allowed to work in pairs (more next time).

One Last Warning From an Internet Comments Section


30/51

One Last Warning From an Internet Comments Section..

From the comments of 15 Programming Languages You Need to Know in 2015
http://mashable.com/2015/01/18/programming-languages-2015/?utm_cid=mash-com-fb-tech-linkhttp://mashable.com/2015/01/18/programming-languages-2015/?utm_cid=mash-com-fb-tech-linkhttp://mashable.com/2015/01/18/programming-languages-2015/?utm_cid=mash-com-fb-tech-link


31/51

Hello World

(See Course Website for In-Class Coding Code

(Might be a little boring if you know Java alrea

Java Observations


32/51

Java Observations

All Java programs are object oriented.

Every Java file must define a class, and that c

must have the same name.

To run a Java program, you must create a public

void main(String[] args).

More Java Observations


33/51


Java isstatically typed.

Every variable, parameter, and function must have a defined ty

choice is permanent.

These types are checked for consistency before program can ru

Good:

It is more efficient. Code runs faster because interpreter doesn

types. Catch some errors before the user ever runs your mobile game

trying to take their money.

Code is easier to reason about.

Bad:

Code is less general, and more verbose.

Citations


34/51

Citations

Real-time MRI by the New Scientist: https://www.youtube.com/watch?v=8XQlIvlWqpo

Self-driving car image by The Guardian:

http://www.theguardian.com/technology/2014/may/28/google-self-driving-car-how-does-it-work

Dance Dance Revolution videos from:

https://www.youtube.com/watch?v=OVtnnIifaU8

https://www.youtube.com/watch?v=12lSScKSx20
https://www.youtube.com/watch?v=12lSScKSx20https://www.youtube.com/watch?v=OVtnnIifaU8http://www.theguardian.com/technology/2014/may/28/google-self-driving-car-how-does-it-workhttps://www.youtube.com/watch?v=8XQlIvlWqpo


35/51

Slides That Follow This Are Obsolete

Java Observations


36/51

All Java programs are object oriented.

All code must live in a class!

If we define a class named Potato, this definition must go in Pot

If we want something to happen when we run the program, we

create a public static void main(String[] args)

Functions are called methods in Java.



37/51

Java is statically typed.

Before we can use a variable, we permanently set its type.

Functions and their parameters must have declared types.

Before a program can even run, it is type checked.

The good:

You can catch some errors before the user tries running your pr

Makes code more readable. Programmer knows EXACTLY what getting.

Code runs faster.

The bad:

Code is more verbose.

Java Observations


38/51

All Java program are object oriented.

All code must live inside a class.

A class Uh.java must define a class Uh.

If we want to run a Java program, we must create a public st

void main(String[] args)



39/51


Before we can use a variable, we make a permanent decision ab

type.

All functions have a declared return type.

Before a program even runs, it is complete type checked.

The good:

Code will execute more efficiently (less space, less time). Easier to reason about what a program does.

Prevents runtime errors. Errors are caught before user gets the

The bad:

Code is more verbose. Well have to generics.

Whats Next


40/51

This week:

HW0: Out now. Will give you a chance to explore Java basics on

Lab 1: How to compile and run code on the lab machines. How

homework starter files and submit them. If possible, do HW0 b

Lab 1B (optional): How to compile and run code on your own m

Friday lecture: What all that public static blah blah stuff actually


41/51

Solutions to slides developed in class

Java Observations


42/51




43/51


Java Observations


44/51




45/51


Every variable and function must have a declared type.

Decision is permanent.

Before a Java program runs, it is type checked. If type checkingprogram doesnt even start.

Good:

Easier to reason about code (you know what all your variables a Catch errors more easily (and before they reach users).

Code will run more efficiently (in memory usage and in time).

Bad:

More verbose (often much more verbose)

Java Observations


46/51

Java is object oriented.

Every piece of code must be associated with a class.

Every .java file must define a class:

A Java file Potato.java must define a class called Potato. To run a Java class, you must define a method called main that

signature public static void main(String args[])

When Potato is run, its main method is called.



47/51


Every variable and method (a.k.a. function) must have a defined

This type can never change.

Before code runs, it must pass a type check: Example of a failed type check: int x = monkeys;

Good things:

Catches some bugs before they reach the person running y

Easier to reason about code since variables have known typ

Code can run more efficiently (less space and time).

Bad things

Code is more verbose and redundant (sometimes extremel

Java


48/51

Java is object oriented:

All code must be part of a class. Define classes with public clas

A class Potato.java must define a class called Potato.

To run a class, we must define a function called main. Functionsare called methods in Java.

Will discuss reasons over the next several weeks.

Java


49/51

Java is statically typed, and types are checked BEFORE program runs

All variables must be declared with a specific type before use.

All methods return a specific type.

The Good: Easier to catch programming errors.

Typing provides implicit documentation.

More efficient execution (no run-time type checking).

The Bad:

Java code is more verbose, e.g. need a separate larger metdoubles, etc.

Java Observations


50/51

Java is object oriented.

Every piece of code needs to be associated with a class.

To execute a class, define a method called main, it will run whe

executed. public static void main(String[] args)

The top-level class of a .java file must have the same name as th

itself.



51/51


Before we can use a variable, it must have a specified type.

This type can never change.

Any expressions involving a variable (or other entity) of a speciffollow the rules.

Example of not following the rules:

int x = potatobrains;

Type checking is performed BEFORE THE CODE EVER RUNS!

Prevents errors from reaching people using your code. Easier to find errors.

Static types:

Allow for more efficient code execution.

Also provided a limited amount of documentation.

cs61b lecture 1 beginning day 1

Documents