WELCOMETOCOMPUTERPROGRAMMING

LjubovJaanuska

MScincomputerscience

TeachingAssistantinInforma6cs

Ins6tuteofComputerScience,UniversityofTartu

ljubov.jaanuska@ut.ee

WHATABOUTYOU?

Name?

Whatareyoustudying?

Whereareyoufrom?

Previousexperience?

Whyshouldwelearnprogramming?

???

Courseoverview

Materials-hIps://courses.cs.ut.ee/

Tests,submissionofexercises,points-

hIps://moodle.ut.ee/

Grading

hIps://courses.cs.ut.ee/2017/nkp/fall/Main/Grading

•  Tests•  Homework+par6cipa6oninthesessions

•  Project(formula6on+solu6on)

•  Mid-termtest

•  Exam(testonpaper+programmingexercise)

Sessions

• Before:• Video• Test• Homework

• Sessions• Wednesday

• Thursday

SoKware

• Python2orPython3• IDLEorNotepad++• CMD???

QuesMonnaire

hIps://goo.gl/forms/7oI4hpqhQjiOWMru1

Bynow…

• Independentlycovered2chaptersofCharlesSeverance:• 2videoslectures• 1test

PROGRAMMING

•  Computerswanttobehelpful

butweneedtospeaktheirlanguage

• Programmersarepeoplewhoknowhowtocommunicatewithcomputers

inaprogramminglanguage.

Theyknowhowtowriteprograms

• Programisasequenceofstoredinstruc6ons(commands)

• Programmersfigureoutthesequenceandencodeit

>WRITEABOOK>ERROR

Python

• Python• AprogramminglanguagedevelopedbyGuidovanRossumin1991

• Awaytocommunicatewithcomputersandencapsulateour

instruc6ons

Advice

Atthebeginning,thelanguageisnew.Itishardlypossibletopickupa

languageoverthenight.

Therewillbelotsofmistakes(e.g.syntaxerror):•  PCisnotcruelnormakingjokes

•  Itsays:“Idon’tunderstandwhatyouaresaying.Ionlyknowafewwords.PleasespeakinPython.”

•  BereadythatPCdon’tcorrectyouasteachersdo.TheycanhardlylistenorunderstandourawkwardShakespearianPython

Keepgoing,wonderingthroughout,ediMng,playing,understanding•  ItiseasierforyoutolearnPythonthantomakecomputersunderstandEnglish

WHY PYTHON?

Python:

print"Hello,world!"

Java:

publicclassHelloWorld{

publicsta6cvoidmain(String[]args){

System.out.println("Hello,world!");

}

}

InteracMveorScript•  InteracMvePython•  Youtypedirectlyonelineata6meandPythonresponds

•  Isgoodforexperimentsandprogramsof3-4lines

• PythonScript•  Youenterasequenceofstatements(lines)intoafileusingatexteditorand

tellPythontoexecutethestatementsinthefile

•  add.pyasthesuffixontheendofthesefilestoindicatetheycontainPython

Chapter2-Expressions• Variables• mnemomicallynamedplaceinthememorywhereaprogrammercanstore

dataandlaterretrievedatausingthevariablename

• MuststartwithaleIerorunderscore_

• MustcontainleIers,numbersorunderscore

•  CasesensiMve

• Constants•  Numbers,leIers,andstringareconstants

•  Theydonotchangetheirvalue•  123 98.6 ‘Hello, world’ “Hello, world”

•  type() •  Types int float str •  Typeconversion int() float() str()

Expressions•  Assignmentstatement

•  e.g.x = 2 •  Hey, Python, go and find a place called ‘x’ and store there 2

•  Assignmentwithexpression(e.g.x = x + 2 )

•  Operators •  Addition + •  Substracion - •  Multiplication * •  Division / Truncateddivision450 / 100resultis4 vs 450.0 / 100 resultis4.5

•  Power ** •  Remainder or moder % (450 % 100 resultis50)

OrderofevaluaMon(operatorprecedence) () ** */% +-leptoright

Expressions

• Reservedwords(e.g.print, for, elif, while)• Userinputraw_input(‘Hello’) • Comments #

Test1

Ques6ons?