CSE 120 9/8/05

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Introduction to Programming
with Java, for Beginners
Welcome
Course Information
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Instructor:
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Teaching Assistants:
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Diana Palsetia (palsetia@seas.upenn.edu)
Junshi Lu (jlu2@seas.upenn.edu)
Yu Tazawa (ytazawa@seas.upenn.edu)
Andrew Xue (andrewx@seas.upenn.edu)
Meeting Times:
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MWTR: 1-2 pm in Moore 207
TR: 10-12 pm in Moore 207
F: 2-4pm in Moore 204 (Robotics/Engineering Lab)
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Our Web Site
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This site is our primary communication vehicle:
http://www.seas.upenn.edu/~pfpcse
 Become familiar with it! :)
 Visit the Resources page
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For homework/lab work submission (BlackBoard)
https://courseweb.library.upenn.edu
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Logistics
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Attendance
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Required: daily lecture/lab
Optional: office hours, quiz review sessions
Grades
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Attendance and participation: 10%
Labwork: 20%
Homework:30%
Quizzes: 40% (2-3 quizzes)
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Late Policy for labwork and homework: 20% off up to 24
hrs.
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No makeup quizzes are scheduled. Conflict? Schedule
in advance
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Computer Science (CS)
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Computer Programming is sub-field of
Computer Science
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It involves learning how to translate a complex
problem/simulation/game in to a computing
solution
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Computing Examples
Digital Special
Effects
User information
Assurance
Information Security
Databases
High Performance Simulation
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Computing
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Formal Definition:
 The use of a computer
process data or
perform calculations
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Early computers were
people
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Advancement in
electronics enabled
computing devices that
were faster than man
Copyright:
http://cannon.sfsu.edu/~gmarcy/cswa/history/pick.html
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CS in General
Computer Science is the study of
 What we can do with computers?
Automate a known solution
 How we can best do it
 Investigate things we don’t know
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 Example:
The Blue Brain Project by EPFL & IBM
started in July 2005
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Understand the brain function and dysfunction to solve
intractable problems in mental health and neurological
disease.
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Three themes in Computing
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Modularity
 Break big problems into simpler sub-problems
 Solve big problems by composing the solutions of
the sub-problems
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Algorithmically
 Having a finite list of well-defined instructions for
accomplishing some task
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Abstraction
 Find common features and express solutions in
terms of those features
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How does CS fit with Engineering?
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Computer Science partners well with many fields:
finance, engineering, graphics, linguistics, genetics,
multimedia, etc.
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Its theoretical foundation lies in mathematics
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Discrete math, probability, and statistics and logic
Another foundational in electrical engineering
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Building block is electronic hardware (computer
architecture)
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Computer Programming & Programming Languages
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Computer Programming
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Is telling the computer how to do something
Wikipedia Definition: Applies specific programming
languages to solve specific computational problems
with solutions
Programming Languages
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Unlike human languages
Designed for instructing computers to solve problems
The listener (the compiler) is exacting &
unforgiving (grr!)
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Like human languages
They have a grammar that has evolved
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Programming Language Syntax
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Syntax is the grammar of the language
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The Listener a.k.a Compiler will point out
every syntax error
E.g. Baking Cake Recipe: Preheat Oven
 missing temperature
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Error messages may be helpful
Often, they are not
You gain experience with error messages after a
while
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Program
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When you write a computational solution in a
programming language it is known as
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When you ask the computer to carry out your
solution it is known as
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Writing a program
E.g. Directions from point A to point B
Running or Executing a program
E.g. Actually traveling from point A to point B
Computer Software
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Is made of one or more programs
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Semantics
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Semantics is the meaning of the program
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We learn the semantics after we run or execute the program
Basically we observe the output
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After the executing program, the semantics of the
program may or may be correct
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Semantic errors cause your answers to be wrong
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E.g. Baking a Cake Recipe: Add the juice of three onions
 Compiler does not find anything wrong with the above statement
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You may or may not get error messages
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E.g. Error Message – Dividing a number by zero
If your program is not doing what you want it to do, though it
runs, the error is semantic
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Programming -The Craft
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People have different tastes in programming, but
many values are held in common
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Programming is an art as well as a craft
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There are concepts fundamental to all
programming languages
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We will practice the fundamentals using Programming
Language called Java
Java also has additional feature called Object Oriented
Programming (OOP) model
Design problems/programs such that they
correspond to real world entities
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