Problem Solving and Python Programming

GE8151-PSPP

1. KARPAGAM INSTITUTE OF TECHNOLOGY,
COIMBATORE -105
Course Code with Name: GE8151 -Problem Solving and Python Programming
Staff Name / Designation: A.Mahalakshmi / Assistant Professor
Department : Information Technology
Year / Semester : I / I
Department of Information Technology

2. UNIT I -ALGORITHMIC PROBLEM SOLVING
SYLLABUS:
Algorithms, building blocks of algorithms (statements, state,
control flow, functions), notation(pseudo code, flow chart,
programming language), algorithmic problem solving,
simple strategiesfordeveloping algorithms (iteration,
recursion).
Illustrativeproblems: find minimum in a list, insert acardin
a list of sorted cards, guess an integer number in a range,
Towers of Hanoi.
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3. ALGORITHMS
•Step-by-step procedure to solve a problem.
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4. CHARACTERISTICS OF AN ALGORITHM
•The instructions should be in a ordered manner.
•The instructions must be simple and concise.
•They must not be ambiguous.
•The algorithm must completely and definitely
solve the problem.
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5. ADVANTAGES OF ALGORITHM
Easy to understand.
Programs can be easily developed.
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6. Write the algorithm to find the sum and average of
given 2 numbers.
Step1 : Start
Step2 : Read values of A and B
Step3 : Calculate SUM =A+B
Step4 : Calculate AVERAGE = (SUM/2)
Step5 : Print Values of SUM and AVERAGE
Step6 : Stop
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7. BUILDING BLOCKS OF ALGORITHMS
Statement
State
Control Flow
Functions
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8. STATEMENT
•Statement is a single action in a computer.
•In a computer statements might include some of
the following actions,
Input data-information given to the program
Process data-perform operation on a given input
Output data-processed result
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9. STATE
•Transition from one process to another process
under specified condition within a time is
called state.
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10. CONTROL FLOW
•Theprocessofexecutingtheindividual
statementsinagivenorderiscalledcontrol
flow.
•Thecontrolcanbeexecutedinthreeways
Sequence
Selection
Iteration
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11. SEQUENCE
•Alltheinstructionsareexecutedoneafteranother
iscalledsequenceexecution.
•Example:Sumoftwonumbers:
Step1:Start
Step2:Readthevaluesofaandb
Step3:calculatec=a+b
Step4:Displayc
Step5:Stop
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12. SELECTION
•Selectionexecutionisbaseduponthecondition.
•Iftheconditionaltestistrue,onepartofthe
programwillbeexecuted.
•Otherwise,itwillexecutetheotherpartofthe
program.
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13. Write an algorithm to check whether he is
eligible to vote?
Step 1: Start
Step 2: Get age
Step 3: if age >= 18 print “Eligible to vote”
Step 4: else print “Not eligible to vote”
Step 6: Stop
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14. ITERATION
•Setofstatementsareexecutedagainandagainbasedupon
conditionaltest.
•Writeanalgorithmtoprintall‘n’naturalnumbers
Step1:Start
Step2:getnvalue.
Step3:initializei=1
Step4:if(i<=n)gotostep5elsegotostep7
Step5:Printivalueandincrementivalueby1
Step6:gotostep4
Step7:Stop
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15. FUNCTIONS
•Functionisasubprogramwhichconsistsofblockofcode(setof
instructions)thatperformsaparticulartask.
•Algorithmforadditionoftwonumbersusingfunction
Mainfunction
Step1:Start
Step2:Callthefunctionadd()
Step3:Stop
Subfunction
Step1:Functionstart
Step2:Geta,bValues
Step3:addc=a+b
Step4:Printc
Step5:Return
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16. FLOW CHART
•Pictorialrepresentationofanalgorithm.
•Sinceitisavisualrepresentation,ithelpstounderstandthelogicof
theprogram.
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17. Draw a flowchart to find the sum and average
of given two numbers.
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18. Draw a flowchart to find the smallest of given
two numbers.
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19. PSEUDOCODE
•Pseudocodeonlydescribesthelogictodevelopaprogram
anditcanbetranslatedtoanycomputerlanguagecode.
•Keywordsshouldbehighlightedbycapitalizingthem.
•UsingKeywords:
Input:READ,OBTAIN,GET
Output:PRINT,DISPLAY,SHOW
Compute:COMPUTE,CALCULATE,DETERMINE
Initialize:SET,INITIALIZE
Addone:INCREMENT,BUMP
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20. Write a pseudo code to accept two numbers from the
keyboard and calculate the sum and
product of them, also display the result on the
monitor screen.
BEGIN
READ A, B
CALCUALTE Sum=A+B
DISPLAY Sum
END
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21. PROGRAMMING LANGUAGE
•Computerprogramminglanguagesareusedtocommunicate
instructionstoacomputer.
InterpretedProgrammingLanguages
FunctionalProgrammingLanguages
CompiledProgrammingLanguages
ProceduralProgrammingLanguages
ScriptingProgrammingLanguages
MarkupProgrammingLanguages
Logic-BasedProgrammingLanguages
ConcurrentProgrammingLanguages
Object-OrientedProgrammingLanguages
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22. PROGRAMMING LANGUAGE CONTD..
InterpretedProgrammingLanguages
•Aninterpretedlanguageexecuteinstructions
directly,withoutpreviouslycompilinga
programintomachine-languageinstructions.
•Examples:APL,BASIC,ICI,J,Lisp,Lua,M,
Pascal,Perl,Python,Ruby,S-Lang,spin
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23. PROGRAMMING LANGUAGE CONTD..
FunctionalProgrammingLanguage:
•Theyfocusontheapplicationoffunctions.
•Manyfunctionalprogramminglanguagesarebound
tomathematicalcalculations.
Examples:-
•ML,Joy,Kite,Clean,OPAL,Q
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24. PROGRAMMING LANGUAGE CONTD..
CompiledProgrammingLanguages
•Acompiledlanguageisaprogramming
languagewhoseimplementationsaretypically
compilers.
•Examples:Ada,ALGOL,C,C++,C#,
COBOL,etc.
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25. PROGRAMMING LANGUAGE CONTD..
ProceduralProgrammingLanguages
•Procedural(imperative)programmingimplies
specifyingthestepsthattheprogramsshould
taketoreachtoanintendedstate.
•Examples:Bliss,ChucK,CLIST,HyperTalk,
Modula-2,Oberon,Component,Pascal,
MATLAB,PL/C,PL/I,Rapira,RPG
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26. PROGRAMMING LANGUAGE CONTD..
ScriptingLanguages
•Scriptinglanguagesareprogramming
languagesthatcontrolanapplication.
•Examples: AppleScript,BeanShell,
ColdFusion,F-Script,JASS,PHP,VBScript,
WindowsPowerShell
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27. PROGRAMMING LANGUAGE CONTD..
MarkupLanguages
•Amarkuplanguageisanartificiallanguage
thatusesannotationstotextthatdefinehow
thetextistobedisplayed.
•Examples:Curl,SGML,HTML,XML,
XHTML
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28. PROGRAMMING LANGUAGE CONTD..
Logic-basedProgrammingLanguages
•Logicprogrammingisatypeofprogramming
paradigmwhichislargelybasedonformal
logic.
•Examples:ALF,Fril,Janus,Oz,Poplog,
Prolog,ROOP
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29. PROGRAMMING LANGUAGE CONTD..
ConcurrentProgrammingLanguages:
•Itisacomputerprogrammingtechnique,which
executestheoperationconcurrently–eitherwithin
singlecomputeroracrossnumberofsystems.
Examples:
•ABCL,ConcurrentPascal,E,Joule,SALSA,Pict,
SR,etc.
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30. PROGRAMMING LANGUAGE CONTD..
Object-OrientedProgrammingLanguages
•Object-orientedprogramming(OOP)isa
programmingparadigmbasedontheconceptof
“objects”,whichmaycontaindata,intheformof
fields,oftenknownasattributes;andcode,inthe
formofprocedures,oftenknownasmethods.
•Examples:IO,Slate,Self,Scala,Prograph,
Oxygene,Moto,MOO,Lava,BETA,Agora
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31. ALGORITHMIC PROBLEM SOLVING
➢Understandingtheproblem
➢Ascertainthecapabilitiesofthecomputational
device
➢Exact/approximatesolution
➢Decideontheappropriatedatastructure
➢Algorithmdesigntechniques
➢Methodsofspecifyinganalgorithm
➢Provinganalgorithmscorrectness
➢Analyzinganalgorithm
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32. UNDERSTANDING THE PROBLEM
•The problem given should be clearly and
completely understood.
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33. DETERMINING THE CAPABILITIES OF
THE COMPUTATIONAL DEVICE
•After understanding the problem, speed and
memory availability of the device are to be
noted.
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34. EXACT /APPROXIMATE SOLUTION
•Oncealgorithmisdevised,itisnecessarytoshowthat
howitcomputesanswerforallthepossiblelegal
inputs.
•ExamplesofExactsolutionproblemsare
i)Computingadditionof2numbers.
ii)Findthegivennumberisprimeornot.
ExamplesofApproximatesolutionproblemswherean
exactsolutioncannotbeobtainedare
i)Findingasquarerootofnumber.
ii)Solutionsofnonlinearequations.
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35. DECIDE ON THE APPROPRIATE DATA
STRUCTURE
•Datatypeisawelldefinedcollectionofdatawiththewell
definedsetofoperationsonit.
•Adatastructureisbasicallyagroupofdataelements.
•TheElementarydatastructuresareasfollows,
List:Allowsfastaccessofdata
Sets:Treatdataaselementofaset.Allowsapplicationof
operationssuchasintersection,Unionandequivalence.
Dictionaries:Allowsdatatobestoredasakeyvaluepair.
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36. ALGORITHM DESIGN TECHNIQUES
•Creatinganalgorithmisanart.
•Bymasteringthesedesignstrategies,itwill
becomeeasiertodevisenewanduseful
algorithms.
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37. METHODS OF SPECIFYING AN
ALGORITHM
•Use of natural language or pseudocode.
•Flow Chart
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38. PROVING AN ALGORITHMS
CORRECTNESS
•Itisnecessarytoprovethatalgorithm
computessolutionsforallthepossiblevalid
input.
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39. ANALYZING THE PERFORMANCE OF
ALGORITHMS
•Analgorithmisanalyzedtomeasureits
performanceintermsofCPUtimeandmemory
spacerequiredtoexecutethatalgorithm.
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40. SIMPLE STRATEGIES FOR DEVELOPING
ALGORITHMS (ITERATION,
RECURSION)
ITERATION
•ALoopisoneormoreinstructionsthatthecomputer
performsrepeatedly.
•Algorithm:Writethealgorithmtoprint“1to5”
Step1:Start
Step2:Initializethevalueofias1
Step3:Printiandincrementthevalueofi
Step4:RepeattheStep3untilthevalueofi<=5.
Step5:Stop
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41. RECURSION
•Afunctionthatcallsitselfisknownasrecursivefunctionandthe
phenomenoniscalledasrecursion.
•Algorithm:Writeanalgorithmtofindthefactorialofagiven
number
MainProgram:
Step1:Start
Step2:Readn
Step3:Callthesubprogramasf=fact(n)
Step4:printfvalue
Step5:Stop
SubProgram:
Step1:Ifn==0orn==1return1tothemainprogramotherwisegoto
step2
Step2:returnn*fact(n-1)tomainprogram
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42. FINDING MINIMUM IN A LIST
Step1:Start
Step2:ReadthelistofnumbersasL
Step3:SetMintolist[0]
Step4:ForeachnumberxinthelistL,compareit
tomin
Step4a:Ifxissmaller,thenassignmintox
Step5:Printmin
Step6:Stop
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43. GUESS AN INTEGER NUMBER IN A
RANGE
Step1:Start
Step2:Generatearandomnumberinbetween1and100
Step3:Gettheguessednumberfromtheuser
Step4:Iftherandomnumberisequaltotheguessednumber
printguessingiscorrect.
Step5:OtherwiseIftherandomnumberisgreaterthanthe
guessednumberprintguessingistoohighandgoto
step7
Step6:Otherwiseprintguessingistoohighandgotostep7.
Step7:Stop
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44. INSERT A CARD IN A LIST OF SORTED
CARDS
Step1-Start
Step2-Readthelistofsortedcards.
Step3-Ifitisthefirstcard,itisalreadysorted.return1;
Step4-Picknextcard
Step5-Comparewithallcardsinthesortedsub-list
Step6-Shiftallthecardsinthesortedsub-listthatis
greaterthanthevalueofthecardtobeinserted.
Step5-Insertthecard
Step6-Repeatuntillistissorted.
Step7-Stop
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45. TOWERS OF HANOI
•Problem:
•TowerofHanoiisamathematicalpuzzlewith
threerodsand‘n’numberofdisks.
•Thesedisksareindifferentsizesandstacked
uponinanascendingorder,i.ethesmallerone
sitsoverthelargerone.
•Theobjectiveistomoveallthediskstosome
anothertowerwithoutviolatingthesequence
ofarrangement.
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46. RULES TO BE FOLLOWED
•Only one disk can be moved among the towers
at any given time.
•Only the “top” disk can be removed.
•No large disk can sit over a small disk.
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48. VIDEO TUTORIAL
S.NO TOPIC LINK
1 Minimuminalist https://youtu.be/5Y1rxCMY_jU
2 InsertaCardinalistof
SortedCards
https://youtu.be/Mow8rdOKrbY
3 Guessanintegernumber
inarange
https://youtu.be/pmDKRJdqT1E
4 TowerofHanoni https://youtu.be/hKUwLe7bpwo
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49. SUMMARY OF UNIT I
•Algorithm, Flow chart, Pseudo code
•Building Blocks of an Algorithm
•Algorithmic Problem Solving Technique
•Simple Strategies for developing an algorithm
•Illustrative Problems for developing an algorithms
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50. ASSIGNMENT QUESTION S
S.NO QUESTIONS BLOOMS LEVEL
1 Applytherulesofanalgorithmand
pseudocodetofindwhetherthegiven
numberispositive,negativeandzero.
K3
2 Applytherulesofanalgorithmand
pseudocodetofindthefactorialofagiven
numberusingrecursion.
K3
3 Writeapseudocodeforconvertingcelsius
ofagivenvalueintofahrenheit.
K3
4 Developaflowchartforperforming
TowersofHanoioperation.
K5
5 Designaflowchartforcalculatingsimple
interest
K5
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51. QUIZ-TEST YOUR KNOWLEDGE
•https://docs.google.com/forms/d/e/1FAIpQLSe
crZ0M-AnDkGI5HOSpzjHrHiDacakocv_-u2K
s_zul55YF0w/viewform
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52. UNIT II DATA, EXPRESSIONS, STATEMENTS
SYLLABUS:
Pythoninterpreterandinteractivemode;valuesandtypes:int,
float,boolean,string,andlist;variables,expressions,statements,
Tupleassignment,precedenceofoperators,comments;modules
andfunctions,functiondefinitionanduse,flowofexecution,
parametersandarguments;
Illustrativeprograms:exchangethevaluesoftwovariables,
circulatethevaluesofnvariables,distancebetweentwopoints.
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53. PYTHON INTERPRETER AND INTERACTIVE MODE
INTERACTIVE MODE PROGRAMMING:
•Interactivemodeisacommandlineshellwhichgives
immediatefeedbackforeachstatement.
•Inthismode,thepromptsforthenextcommandusuallyhave
threegreater-thansigns(>>>).
•Example-A sample interactive session:
>>> 5
5
>>> print(5*7)
35
>>> "hello" * 4
'hellohellohellohello'
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54. PYTHON INTERPRETER AND INTERACTIVE MODE
CONTD..
SCRIPT/INTERPRETER MODE PROGRAMMING
•In script mode, execution of the script begins and continues
until the script is finished.
•Example:
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55. VALUES AND TYPES
•VALUE–refers to the basic things in a program works which
can be like a letter or a number.
•TYPE-refers to the data type, which is used to find the type
of data.
Following are the various basic types of a value:
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S.NO TYPES EXAMPLE OF VALUES
1 Int 10,100,-256,789656
2 Float 3.14,2.56789,-21.9
3 Boolean True or False
4 String “Hai” or ‘Hi’
5 List [0,1,2,3,4]
6 Tuple (0,1,2,3,4)
7 Dictionaries {1:“Hai”, 2: “Welcome”}

56. VALUES AND TYPES CONTD..
•INTEGER-it is represented by a whole number.
>>>type(3)
<type ‘int’>
•FLOAT-Numbers with a decimal point
>>>type(3.2)
<type 'float'>
•BOOLEAN-it is represented by TRUE or FALSE
>>> bool(1)
True
>>> bool(0)
False
>>>type(2>3)
<class ‘bool’>
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57. VALUES AND TYPES CONTD..
•STRING -values with quotes like single, double, triple
>>>type('17')
<type 'str'>
•LIST-collection of elements in square bracket [ ]
>>>a=[1,2,3]
>>>type(a)
<tupe‘list’>
•TUPLE -collection of elements in paranthesis( )
>>>a=(1,2,3)
>>>type(a)
<type ‘tuple’>
•DICTIONARY–Collectionofelementsincurlybraces{}withkey:value
pair
>>>a={1: “hai”, 2: “welcome”}
>>>type(a)
<type ‘dict’>
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58. VARIABLES
•Variables are defined as reserved memory locations to store
values.
Rules for Naming Variables
•Variable names can contain letters, symbols like underscore
(__) and numbers.
•They begin with a letter not numbers.
•Both uppercase and lowercase letters are used.
•Keywords cannot be used as variable names.
•Example for valid identifier
•abc, xy12, good_start
•Example for non-valid identifier
•12xy, x$y
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59. EXPRESSIONS
•Anexpressionisacombinationofvalues,variables,
andoperators.
•Examples:
–17
–x
–x+17
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60. STATEMENTS
•Eachandeveryinstructionorlineintheprogramis
calledasstatements.
•Example:
A=10 #assignmentstatement
B=20 #assignmentstatement
C=A+B #assignmentstatement
print(C) #printstatement
Output:
30 #outputstatement
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61. TUPLE ASSIGNMENT
•Python has a very powerfultuple assignmentfeature that
allows a tuple of variables on the left of an assignment to be
assigned values from a tuple on the right of the assignment.
•For example, to swapaandb:
a=10
b=20
temp = a
a = b
b = temp
•Tuple assignment solves this problem neatly:
(a,b) = (b,a)
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62. PRECEDENCE OF OPERATORS
ORDER OF OPERATIONS:
•When more than one operator appears in an expression, the
order of evaluation depends on the rules of precedence.
•The acronym PEMDAS is a useful way to remember the rules:
–Parentheses have the highest precedence
•2 * (3-1) is 4, and
•(1+1)**(5-2) is 8.
-Exponentiation has the next highest precedence
•2**1+1 is 3, not 4, and
•3*1**3 is 3, not 27.
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63. PRECEDENCE OF OPERATORS CONTD..
•Multiplication and Division have the same precedence, which
is higher than Addition and Subtraction, which also have the
same precedence.
–2*3-1 is 5, not4, and
–6+4/2 is 8, not 5.
•Operators with the same precedence are evaluated from left to
right (except exponentiation).
–So in the expression degrees / 2 * pi, the division happens
first andthe result is multiplied by pi.
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64. PRECEDENCE OF OPERATORS CONTD..
Operator Description
** Exponentiationraise to the power
~ ,+,- Complement, unary plus and minus
*, /,%, // Multiply, divide, modulo and floor division
+, - Addition and subtraction
>> , << Right and left bitwise shift
& Bitwise 'AND'
^, | Bitwise exclusive `OR' and regular `OR'
<=, <, >, >= Comparison operators
<>, ==, != Equality operators
=, %=, /=, //=, -=, +=, *=, **= Assignment operators
is, is not Identity operators
in, not in Membership operators
not or and Logical operators
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65. COMMENTS
•Comment is a piece of program text that the interpreter ignores
but that provides useful documentation to programmers.
•Comments start with the # symbol
Example:
# compute the sum of two numbers
C=A+B
•In this case, the comment appears on a line by itself. We can
also put comments at the end of a line
C=A+B #sum of two numbers
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66. MODULES AND FUNCTIONS
•Module is a file consisting of Python code.
•A module can define functions, classes and variables.
Example:
a="Dora"
def print_func(a):
print ("Hello : ", a)
return
print_func(a)
Output:
Hello : Dora
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67. MODULES AND FUNCTIONS CONTD ..
•The modules can be imported by the following ways:
The import statement
Thefrom...importStatement
The from...import *Statement
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68. MODULES AND FUNCTIONS CONTD ..
The import statement
•WecanuseanyPythonsourcefileasamoduleby
executinganimportstatementinsomeotherPython
sourcefile.
•Theimporthasthefollowingsyntax,
importmodule1,module2,…….moduleN
Example-
importmath
print(math.sqrt(4))
Output
2.0
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69. MODULES AND FUNCTIONS CONTD ..
The from….import statement
•In Python’s from statement, lets us import specific attributes
from a module into the current namespace.
•The from…import statement has the following syntax,
from modnameimport name1, name2,…nameN
Example-
moduleAccess.py
from sample import a,b
print(a.A())
print(b.B())
Output:
Hai
Hello
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a.py
def A():
print(“Hai”)
b.py
def B():
print(“Hello”)
sample.py

70. MODULES AND FUNCTIONS CONTD ..
Thefrom….import*statement
•Itisalsopossibletoimportallnamesfromamodule
intothecurrentnamespacebyusingthefollowing
importstatement,
frommodnameimport*
•Thisprovidesaneasywaytoimportalltheitems
fromamoduleintothecurrentnamespace.
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71. FUNCTION DEFINITION AND USE
FUNCTION
Functionisablockofcode,thatareexecutedwhenitiscalled.
Functionblocksbeginwiththekeyworddeffollowedbythe
functionnameandparentheses().
Anyinputparametersorargumentsshouldbeplacedwithin
theseparentheses.
Thecodeblockwithineveryfunctionstartswithacolon(:)and
isindented.
Thestatementreturn[expression]exitsafunction,optionally
passingbackanexpressiontothecaller.
Areturnstatementwithnoargumentsisthesameasreturn
None.
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72. FUNCTION DEFINITION AND USE CONTD..
Syntax-
def functionname( parameters ):
function_suite
return[expression]
Example-
def printme(str):
print (str)
return
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73. FUNCTION DEFINITION AND USE CONTD..
USES OF FUNCTION-
It makes the program size smaller.
It involves the concept of modularity.
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74. FLOW OF EXECUTION
Theorderinwhichstatementsareexecuted,whichis
calledtheflowofexecution.
Executionalwaysbeginsatthefirststatementofthe
program.
Statementsareexecutedoneatatime,inorderfrom
toptobottom.
Duringfunctioncall,theargumentsintheactual
parametersareassignedtotheformalparameters.
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75. FLOW OF EXECUTION CONTD..
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76. FLOW OF EXECUTION CONTD..
Example-
a=10
b=20
def sum(c,d):
e=c+d
return e
print("Result is :",sum(a,b))
Output:
30
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77. PARAMETERS AND ARGUMENTS
•Parametersprovidethedatacommunicationbetween
callingfunctionandcalledfunction.
Twotypes:
Actualparameter-Thisistheargumentwhichis
usedinfunctioncall.
Formalparameter-Thisistheargumentwhichis
usedinfunctiondefinition.
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78. PARAMETERS AND ARGUMENTS CONTD..
ARGUMENTS -refers to the value.
Types of Arguments
Required arguments
Keyword arguments
Default arguments
Variable-length arguments
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79. PARAMETERS AND ARGUMENTS CONTD..
REQUIREDARGUMENTS
Requiredargumentsaretheargumentspassedtoafunction
incorrectpositionalorder.
Example
defsum(a,b):
c=a+b
returnc
print("Resultis:",sum(10,20))
Output:
30
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80. PARAMETERS AND ARGUMENTS CONTD..
KEYWORD ARGUMENTS
Here,thecalleridentifiestheargumentsbytheparameter
name.
Example
defsum(a,b):
c=a+b
returnc
print("Resultis:",sum(a=10,b=20))
Output:
30
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81. PARAMETERS AND ARGUMENTS CONTD..
DEFAULTARGUMENT:
Defaultargumentisanargumentthatassumesadefault
valueifavalueisnotprovidedinthefunctioncallforthat
argument.
Example
defsum(a=10,b):
c=a+b
returnc
print("Resultis:",sum(20))
Output:
30
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82. PARAMETERS AND ARGUMENTS CONTD..
VARIABLE-LENGTH ARGUMENT
This is used to process a function with more argument.
Syntax for a function with variable length argument,
def functionname([formal_args,]*var_args_tuple):
function_suite
return[expression]
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83. PARAMETERS AND ARGUMENTS CONTD..
Example for Variable-length Argument
def printinfo( arg1,*vartuple):
print ("Output is: ")
print ( arg1)
for varin vartuple:
print (var)
return;
printinfo(10)
printinfo(70,60,50)
Output
10
Output
70
60
50
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84. EXCHANGE THE VALUE OF TWO VARIABLES
With Temporary Variable
x = input("Enter value of x:")
y = input("Enter value of y:")
temp = x
x = y
y = temp
print('The value of x after swapping:',x)
print('The value of y after swapping:',y)
Output
Enter value of x: 67
Enter value of y: 45
The value of x after swapping: 45
The value of y after swapping: 67
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85. EXCHANGE THE VALUE OF TWO VARIABLES CONTD..
Without Temporary Variable
x = input("Enter value of x:")
y = input("Enter value of y:")
x= x + y
y = x -y
x = x -y
print('The value of x after swapping:',x)
print('The value of y after swapping:',y)
Output
Enter value of x: 67
Enter value of y: 45
The value of x after swapping: 45
The value of y after swapping: 67
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86. CIRCULATE THE VALUES OF N NUMBERS
def circulate(A,N):
for i in range of(0,N):
j=len(A)-1
while j>0:
temp=A[j]
A[j]=A[j-1]
A[j-1]=temp
j=j-1
print(‘Circulation\t’,A)
return
A=[91,92,93,94,95]
n=int(input(“Enter n:”))
circulate(A,n)
Output
n=2
Circulation 95,91,92,93,94
Circulation 94,95,91,92,93
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87. DISTANCE BETWEEN TWO POINTS
import math
x1=int(input("Enter the X-Coordinate of first point"))
y1=int(input("Enter the Y-Coordinate of first point"))
x2=int(input("Enter the X-Coordinate of Second point"))
y2=int(input("Enter the Y-Coordinate of Second point"))
distance = math.sqrt( ((x1-x2)**2)+((y1-y2)**2) )
print(distance)
Output
Enter the X-Coordinate of first point 4
Enter the Y-Coordinate of first point 0
Enter the X-Coordinate of Second point 6
Enter the Y-Coordinate of Second point 6
6.324555320336759
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88. VIDEO TUTORIAL
S.No Topic Link
1Interpreter and Interactive modehttps://youtu.be/3lvgY5V8494
2Operator and it's types with their
Precedence
https://youtu.be/ljaw6cUobtU
3Circulate the value of n numbers
using slicing operator
https://youtu.be/1Y46EaJAQ4c
4Distance between two pointshttps://youtu.be/qeZ5kiKJe7c
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89. SUMMARY
Python Interpreter and Interactive mode
Values and Data types
Operators and its Precedence
Modules and Functions
Function Parameters and Arguments
Illustrative Problems
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90. ASSIGNMENT QUESTIONS
S.No Questions Blooms Level
1Write a Python programs to check
whether the given number is palindrome
or not
K3
2Apply the concept of Modules for airlines
system
K3
3Distinguish between Interpretermode and
Interactive mode
K4
4Develop a Python program for finding
Fibonacci sequence of n numbers using
function with recursion
K5
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91. QUIZ -TEST YOUR KNOWLEDGE
•https://forms.gle/uP745eEsYzko6Y2U9
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92. UNIT III CONTROL FLOW, FUNCTIONS
SYLLABUS
Conditionals: Boolean values and operators, conditional (if),
alternative (if-else), chainedconditional(if-elif-else);
Iteration: state, while, for, break, continue, pass; Fruitful
functions: returnvalues, parameters, local and global scope,
function composition, recursion; Strings: string slices,
immutability, string functions and methods, string module;
Lists as arrays.
Illustrativeprograms: square root, gcd, exponentiation, sum
an array of numbers, linear search, binary search.
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93. BOOLEAN EXPRESSION
ABooleanexpressionisaexpressionthatresultsineithertrue
orfalse.
Itusesthe==operatorwhichcomparestwooperandsand
procedurestrueifbothareequalotherwisefalse.
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94. CONTROL FLOW
•Itisastatementthatdeterminesthecontrolflowofasetof
instructions.,(ie)itdecidesthesequenceinwhichthe
instructionsinaprogramaretobeexecuted.
•Itcaneithercompriseofoneormoreinstructions.Three
fundamentalcontrolstatementsare
Sequential
Selection
Iterativecontrol
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95. TYPES OF DECISION CONTROL STATEMENTS
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96. SELECTION OR CONDITIONAL BRANCHING
STATEMENT
•Thedecisioncontrolstatementsusuallyjumpsfromonepartof
thecodetoanotherdependingonwhetheraparticular
conditionissatisfiedornot.
•Pythonselectionstatementsare:
Ifstatement
If-elsestatement
If-elif-elsestatement
Nested-ifstatement
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97. ITERATIVE STATEMENTS
•Iterativestatementsaredecisioncontrolstatementsthatare
usedtorepeattheexecutionofalistofstatements.The
followingarethetypesofiterativestatements.
whileloop
forloop
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98. WHILE LOOP
•Thewhileloopprovidesamechanismtorepeatoneormore
statementswhileaparticularconditionistrue.
•Syntax:
Statement X
while (condition):
Statements block
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99. FLOWCHART FOR WHILE LOOP
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100. EXAMPLE FOR WHILE LOOP
num= 1
while num < 10:
print(num)
num = num + 3
Ouput:
1
4
7
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101. EXAMPLE FOR WHILE LOOP WITH ELSE STATEMENT
num = 10
while num > 6:
print(num)
num = num-1
else:
print("loop is finished")
Output:
10
9
8
7
loop is finished
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102. FOR LOOP
•Itprovidesamechanismtorepeatataskuntilaparticular
conditionistrue.
•Itisknownasdeterminateordefiniteloopbecausethe
programmerknowsexactlyhowmanytimestheloopwill
repeat.
Syntax1:
forloop_control_varinsequence:
Statementblock
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103. FOR LOOP CONTD..
Syntax 2:
for variable in range(beg,end,[step]):
Statements
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104. FLOWCHART OF FOR LOOP
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105. EXAMPLE OF FOR LOOP
numbers = [1, 2, 4, 6, 11, 20]
sq = 0
for valin numbers:
sq = val* val
print(sq)
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Output:
1
4
16
36
121
400

106. RANGE( ) IN FOR LOOP
•range(n): generates a set of whole numbers starting
from 0 to (n-1).
For example:
range(8) is equivalent to [0, 1, 2, 3, 4, 5, 6, 7]
•range(start, stop): generates a set of whole numbers
starting from start to stop-1.
For example:
range(5, 9) is equivalent to [5, 6, 7, 8]
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107. RANGE( ) IN FOR LOOP CONTD..
•range(start,stop,step_size):Thedefaultstep_sizeis1
whichiswhywhenwedidn’tspecifythestep_size,the
numbersgeneratedarehavingdifferenceof1.However
byspecifyingstep_sizewecangeneratenumbershaving
thedifferenceofstep_size.
Forexample:
range(1,10,2)isequivalentto[1,3,5,7,9]
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108. EXAMPLE OF FOR LOOP WITH RANGE( )
sum = 0
for valin range(1, 6):
sum = sum + val
print(sum)
Output:
15
108
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109. EXAMPLE OF FOR LOOP WITH ELSE BLOCK
for valin range(5):
print(val)
else:
print("The loop has completed execution")
Output:
0
1
2
3
4
The loop has completed execution
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110. BREAK STATEMENT
•Thebreakstatementisusedtoterminatethe
executionoftheloop.
•Whenacompilerencountersabreakstatement,the
controlpassestothestatementthatfollowstheloop
inwhichthebreakstatementappears.
•Syntax:-break
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111. FLOWCHART FOR BREAK STATEMENT
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112. EXAMPLE FOR BREAK STATEMENT
# program to display all the elements before number 88
for numin [11, 9, 88, 10, 90, 3, 19]:
print(num)
if(num==88):
print("The number 88 is found")
print("Terminating the loop")
break
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Output:-
11
9
88
The number 88 is found
Terminating the loop

113. CONTINUE STATEMENT
•Thecontinuestatementcanonlyappearinthebody
ofaloop.
•Whenacompilerencountersacontinuestatement,
thentherestofthestatementsintheloopareskipped
andthecontrolisunconditionallytransferredtothe
loop-continuationportionofthenearestloop.
•Syntax:continue
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114. FLOWCHART FOR CONTINUE STATEMENT
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115. EXAMPLE FOR CONTINUE STATEMENT
# program to display only odd numbers
for numin [20, 11, 9, 66, 4, 89, 44]:
if (num%2 == 0):
continue
print(num)
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Output
11
9
89

116. PASS STATEMENT
•Thepassstatementactsasaplaceholderandusuallyused
whenthereisnoneedofcodebutastatementisstillrequiredto
makeacodesyntacticallycorrect.
•Example:-
fornumin[20,11,9,66,4,89,44]:
ifnum%2==0:
pass
else:
print(num)
Output:
11
9
89
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117. STRINGS
•Stringisasequenceofcharacters.
•Stringmaycontainalphabets,numbersandspecial
characters.
•Stringvaluemustbeenclosedwithineithersingle
quotesorwithindoublequotes.
•Stringisimmutableinnature.(i.e).,oncecreated
cannotbeabletoeditwhenitisstoredinavariable.
Example:
Letter = “A”
Name = ‘python’
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118. READING STRING VALUE FROM THE USER:
•Usinginput()functionwecanreadstringvaluefrom
theuser.
Syntax:
Variable_name=input(“Enterthevalues”)
Example:
Name=input(“Enterthename”)
print(“Welcome”,name)
Output:
Enterthename:python
Welcomepython
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119. INDEX OPERATION:
•Eachcharactercanbeaccessedthroughindexoperator.
Syntax:
String_variable_name[index]
•Indexvaluestartsatzeroandlastindexvalueis(lengthof
thestring-1)
Example:
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120. STRING OPERATIONS
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121. CONCATENATION OF TWO OR MORE STRINGS
•Joiningoftwoormorestringsintoasingleoneis
calledconcatenation.
Syntax:String2=string1+string2
Example:
str1 = 'Hello'
str2 ='World!'
print('str1+str2=',str1+str2)
Output:
HelloWorld!
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122. REPETITION OPERATOR(*):
•Itisusedtoconcatenatethesamestringmultiple
times.
Syntax:
String2=String1*integervalue
Example:
str1='Hello'
print('str1*3=',str1*3)
Output:
HelloHelloHello
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123. STRING SLICING
•Slicingoperationsisusedtoselect/return/slice
theparticularsubstringbasedonuser
requirements.
•Asegmentofthestringiscalledslice.
Syntax:
String_variable_name[start:end:stepvalue]
•Herealltheparameters/variablesareoptional
•Thedefaultvalueforstartiszeroandendisend-1
•Thedefaultvalueforstepis1.
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124. EXAMPLE FOR STRING SLICING
var1 = 'Hello World!’
var2 = "Python Programming"
print "var1[0]: ", var1[0]
print "var2[1:5]: ", var2[1:5]
Output:
H
ytho
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125. STRING COMPARISON:
•We can compare two strings by using comparison
operators such as ==,!=,<,<=,>,>=.
•Python compares strings based on their corresponding
ASCII values.
•For ‘a’ ASCII value is 97 and ‘A’ ASCII value is 65.
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126. EXAMPLE FOR STRING COMPARISON
str1=”green”
str2=”glow”
print(“is both string are equal:”, str1==str2)
print(“is both string are not equal:”, str1!=str2)
print(“is str1>str2:”,str1>str2)
print(“is str1>str2:”,str1<str2)
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Output:-
is both string are equal:False
is both string are not equal:True
is str1>str2:True
is str1>str2:False

127. STRING ITERATION:
•Wecanusforlooptotraverseallthecharactersinthe
stringsequentially.
•Syntax1:
forvar_nameinstring_varaible_name:
statements
•Syntax2:
forvar_nameinrange(initial,final,stepvalue):
statements
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128. PROGRAM TO COUNT THE NUMBER OF
CHARACTERS IN A STRING
str=input(“enter any string:”)
count=0
for letter in str:
if(letter):
count=count+1
print(“total number of characters in string is:”, count)
Output:
Enter any string:python
Total number of characters in string is:6
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129. COUNT THE NUMBER OF CHARACTERS IN A STRING
USING RANGE FUNCTION
str=input(“enter any string:”)
count=0
for letter in range(0,len(str)+1,1):
if(letter):
count=count+1
print(“total number of characters in string is:”, count)
Output:
Enter any string: python
Total number of characters in string is:6
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130. STRING IMMUTABILITY
•Stringsareimmutableinnature.
•Wecannoteditthestringvalueonceitisassignedtovariable.
•Ifwetrytoassignorreplaceavalueinthestring,itdisplays
anerrormessagethatstrisnotamutableobject.
Program:
str=“welcome”
print(str[3])
str[3]=“c”#assigningvaluectoindex3place
print(str)
Output:
c
Traceback(mostrecentcalllast):
str[3]=”c’#assigningvaluectoindex3place
TypeError:’str’objectdoesnotsupportitemassignment
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131. STRING MODULES
•Stringmodulescontainanumberoffunctionsto
processstandardpythonstring.
•Thiscanbedonebyimportingstringfunction.
Syntax:
import string
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132. LIST AS ARRAY:
•Arrayisacollectionofsimilardataitemsthatare
storedunderacommonname.
•Pythonisnotprovidingarraydatatyperatherthanit
providesaLIST.
Implementingarrayinpythonone-dimensionallist:
•Arrayscanbeimplementedasonedimensionallist.
•Ex:Price_list=[70,80,90,93.5,30.456]
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133. MINIMUM VALUE IN THE LIST WITHOUT USING
INBUILT FUNCTION:
price_list=[70,80,90,93.5,30.456]
min=price_list[0]
for min_valuein price_list:
if min>min_value:
min=min_value
print(“minimum value in the list is:”,min)
OUTPUT:
minimum value in the list is:34.56
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134. IMPLEMENTING ARRAY IN PYTHON AS TWO -
DIMENSIONAL LIST:
Example:
Two_dim_array_list=[[1,2],[3,4]]
Program:
two_dim=[[1,2],[3,4]]
print(“original 2 dimensional list:”)
for iin range(len(two_dim)):
for j in range(len(two_dim[i])):
print(two_dim[i][j],end=“”)
print(“\n”)
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135. SQUARE ROOT OF A GIVEN NUMBER:
num=float(input("Enter a Number"))
num_sqrt=num**0.5
print("The square root of %0.3f is %0.3f"%(num,num_sqrt))
Output--
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136. GCD OF TWO NUMBERS
def gcd(a, b):
if(b==0):
return a
else:
return gcd(b, a%b)
a=int(input("Enter First number"))
b=int(input("Enter Second number"))
GCD=gcd(a, b)
print("GCD is:")
print(GCD)
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137. EXPONENTIATION
import math # This will import math module
print ("math.pow(100,2): ", math.pow(100,2))
print ("math.pow(100,-2): ",math.pow(100,-2))
print ("math,pow(2,4): ",math.pow(2,4))
print ("math.pow(3,0): ",math.pow(3,0))
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138. SUM AN ARRAY NUMBERS
def listsum(numlist):
sum=0
for i in numberlist:
sum=sum+i
return sum
print(listsum([1,3,5,9]))
Output:
18
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139. LINEAR SEARCH
my_data=[89,45,9,21,34]
num=int(input(“Enter search num:”))
for i in range (0, len(my_data)):
if num==my_data[i]:
print(“Item is located at position=,”i)
else:
print(“Item not found”)
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140. BINARY SEARCH
list=[10,20,30,40]
x=int(input(“Enter the element to search:”)
first=0
last=len(list-1)
while(first<=last):
mid=(first+last)//2
if(x==list[mid]):
print(“The element is found at the index:”,mid)
break
elif(x<list[mid]):
last=mid-1
else:
first=mid+1
else:
print(“The element is not found in the list”)
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141. VIDEO TUTORIAL
S.NO TOPIC LINK
1Boolean Values and
Operators
https://youtu.be/7vy_GffZZTg
2Loops in Python https://www.youtube.com/watch?v=
zFvoXxeoosI
3Fruitful Functions https://youtu.be/hMGc19ZYzDM
4Stringsin Python https://www.youtube.com/watch?v=
QGLNQwfTO2w
5Linear Search https://youtu.be/fHMXsGkN5cg
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142. SUMMARY
•Pythonbranchingstatements
•Pythonloopingstatements
•Stringsanditsmethods.
•IllustrativePrograms
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143. ASSIGNMENT QUESTIONS
S.NO QUESTIONS BLOOMS LEVEL
1 WriteaPythonprogramtocheckwhethera
givennumberisaperfectnumber
K3
2 WriteaPythonprogramtocalculatethenumber
ofwordsandnumberofcharacterspresentina
string
K3
3 WriteaPythoncodetocounttheoccurrencesof
eachwordinagivenstringsequence
K3
4 DevelopaPythoncodetocheckwhetherastring
ispalindromeornot
K5
5 DevelopaPythonprogramtodetectwhether
twostringsareanagrams
K5
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144. QUIZ-TEST YOUR KNOWLEDGE
•https://docs.google.com/forms/d/e/1FAIpQLSc
Yn1TS4wfhudU0CgVwuCGlEZPQmchmz1_l
av0Q2oiONI8Gbw/viewform
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145. THANK YOU
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