CSC-201 - Computer Science I Lecture #3: Chapter...

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Schedule Miscellanea Chapter 5 Break Test preps. Hands on Q & A Conclusion References Files

CSC-201 - Computer Science ILecture #3: Chapter 5

Dr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck Cartledge

September 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pmSeptember 5, 2016 at 10:19pm

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Table of contents I

1 Schedule

2 Miscellanea

3 Chapter 5

4 Break

5 Test preps.

6 Hands on

7 Q & A

8 Conclusion

9 References

10 Files

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Schedule for the semester

Wk. Date Topic Wk. Date Topic1 08/22 Chaps. 1 2 X 9 10/17 Chap. 102 08/29 Chaps. 3 4 X 10 10/31 Chaps. 10 113 09/05 Chap. 5 11 10/31 Chaps. 10 114 09/12 Test Chap. 6 12 11/07 Test Chap. 145 09/19 Chap. 7 13 11/14 Chap. 146 09/26 Chap. 8 14 11/28 Chap. 187 10/03 Chap. 9 15 12/05 Chap. 188 10/10 Test Chap. 10 16 12/12 Exam

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Corrections and additions since last lecture.

Answered a few questionse-mails about theassignment

Assignment #01 due bybeginning of class

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This and that

Read from a file.

Objectives are fairlystraightforward:

Read strings from a datafile.

Output strings to the screenin a particular format

Submit your source code.

This is a single person effort (nota team effort).

Any questions or problems?

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Conditions, logical expressions, and selection control structures

Flow of control

There are limited number of different flow of control

Sequential instructions are executed in order

Function calls program execution is transferred to a functionand then returned (with or without a return value)

Selection some instructions are executed, but others are not

Looping a set of instructions is executed more than once

Weve talked about sequential, and function calls. Now, welladdress selection.

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C++ operators we will know and love.

There are a lot of declaredoperators in C++. Over the nextfew months will will learn aboutthe ones in red, and possibly theones in green.

Image from [3].

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Same image.

Image from [3].

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With so many operators, which has precedence?

Not all operations are left toright. Precedence can be affectedby using parenthesis.

Image from [4].

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Same image.

Image from [4].

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The if statement.

The if statement, evaluates a conditional as true orfalseWhen the conditional is true then the next statement isexecuted.The conditional can be simple or complex.

Examples of if statements:if ( true ) cout

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The if statement continued.

What is the output/result of these statements?

c = a = 3;

c = a == 3;

if ( a = 3 )

cout

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The if statement some more.

What if we dont want the true case ?

if ( !true ) cout

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The true and false conditions with an ifstatement.

How can we handle both the true and false conditions?

if ( true ) cout

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What if we want to execute more than one statement?

We look at what defines a statement.

if ( true ) cout

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Things are easy with integer numbers.

How about strings?

The logical operators can be used on strings.

Strings are compared, character by character based on theASCII1 coding scheme.

One string can be equal to, less than, or greater than anotherstring.

What happens with non-ASCII strings?

1ASCII is the American Standard Code for Information Interchangehttp://man7.org/linux/man-pages/man7/ascii.7.html

http://man7.org/linux/man-pages/man7/ascii.7.html

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if conditionals with strings.

Do these conditionals evaluate to true or false

string myState = "Texas";

string yourState = "Maryland";

myState == yourState

myState > yourState

myState == "Texas"

myState == "texas"

myState < "texas"

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Can we use conditionals with non-integer numbers

Yes, but they may not work.We talked about this last week. The way floating point numbersare represented in memory means that some decimals can not berepresented accurately.If you have to use floating point variables in conditionals, thendont test for equality, test for close enough.

double epsilon = 0.00001;

if ( fabs (fp1 - fp2)

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How about if there are lots of conditions to test,

And the conditions are somehowrelated??

An if statement is astatement.

An if statement willbranch and execute astatement.

Therefore an if statement canexecute another if statement.Hands-on exercise.

Image from [1].

Hands on exercise.

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Same image.

Image from [1].

Hands on exercise.

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You can test I/O as well.

You can test the state of the Input/Output stream.

An input stream can fail:

Try to read invalid dataTry to open a file that doesnt existTry to read past the end of a file

An output stream can fail:

Try to create a file with an invalid nameTry to create a file on a write-protected mediumTry to create a file on a full disk

After using a stream, you should check its state to see if theoperation was a success.

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Checking I/O example

std::string fileName = "/tmp/temp.txt";

std::ifstream inputFile;

inputFile.open(fileName.c_str());

if ( !inputFile )

{

std::cout

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Testing

Where does testing belong?

Software testing is one element of a broader topicthat is often referred to as verification and validation(V&V). Verification refers to the set of tasks that ensurethat software correctly implements a specific function.Validation refers to a different set of tasks that ensurethat the software that has been built is traceable tocustomer requirements.

Pressman [2]

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Testing

Generic testing classifications

Testing requires enough data sets to ensure that each branch isexecuted at least once.The difference is how much insight you have into the software:

White box testing total visibility into the software

Black box testing no visibility into the software

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Testing

Incremental and regression testing

Two different types of testing that require different types of tools.

Incremental code a little,test a little

Regression stop codingand test a lot. Instrumentcode to see test coverage.

Full regression testing often requires support software.

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Testing

Good testing requires a plan

There are different testing phases, and each needs to be in theplan.

Unit testing a developertests the software instandalone environment

Integration testing a teamtest software from differentdevelopers together

Top-down integrationBottom-up integrationRegression testingSmoke testing

Documentation

Alpha and beta testing

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Break time.

Take about 10 minutes.

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Some ideas

Broad things from different chapters

1 Lots of vocabulary andordering things

2 More vocabulary and basicsyntax

3 Variables of different typesand what you can do withthem

4 Extraction operators andsimple programs

5 if . . . then . . . else andconditionals

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Some ideas

There will be an exam.

Cover chapters 1 through 5(inclusive)

Exam has not been writtenyet

Exam should take about anhour

When finished with exam,leave room with answers

Lecture will start after examends

Any questions? Now is the time to ask.

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Practice exercises

Programs to load into CodeBlocks and get running:

1 testIfStatements.cpp (get the program working)

2 BMI.cpp (trace nested if statements)

3 testIO.cpp (see if you can open a file)

Others, if you have time.

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Q & A time.

The Answer to the GreatQuestion . . . Of Life, the Universeand Everything . . . is. . . forty-two, said DeepThought, with infinite majestyand calm.Douglas Adams, TheHitchhikers Guide to theGalaxy

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What have we covered?

Covered if statementsCovered software testingrequirementsGave hints about what will be onthe testGot our hands dirty with live code

Next time: Test and Chapter 6

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References I

[1] Nell Dale and Chip Weems, Programming and problem solvingwith c++: Comprehensive, Jones & Bartlett Publishers, 2013.

[2] Roger S Pressman, Software engineering: A practitionersapproach, Palgrave Macmillan, 2005.

[3] Richard Smith et al., Working draft, standard for programminglanguage c++, ISO/IEC JTC1/SC22/WG21 document N4296 (2015).

[4] C++ Staff, C++ operator precedence,http://en.cppreference.com/w/cpp/language/

operator_precedence, 2016.

http://en.cppreference.com/w/cpp/language/operator_precedencehttp://en.cppreference.com/w/cpp/language/operator_precedence

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Files of interest

1 BMI.cpp

2 testIfStatements.cpp

3 testIO.cpp

4 virtualization.pdf

BMI.cpp//****************************************************************

//BMIProgram

//Thisprogramcalculatesthebodymassindex(BMI)givenaweight

//inpoundsandaheightininchesandprintsahealthmessage

//basedontheBMI.InputinEnglishmeasures.

//*****************************************************************

#include

usingnamespacestd;

intmain()

{

constintBMI_CONSTANT=703;//Constantinnon-metricformula

floatweight;//Weightinweight

floatheight;//Heightinheight

floatbodyMassIndex;//AppropriateBMI

booldataIsOK;//Trueifdatanon-negative

//Promptforandinputweightandheight

cout

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How do programs operate? What is Virtualization? What is it good for? What is it not good for? Conclusion References

CS-495/595Big Data

Virtualization

Dr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck CartledgeDr. Chuck Cartledge

21 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 201521 Jan. 2015

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Table of contents

1 How do programs operate?

2 What is Virtualization?

3 What is it good for?

4 What is it not good for?

5 Conclusion

6 References

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A 50,000 foot view

What are the layers in this cake?

User the person (orthing) that wantssomething done

Application the programthat does the work

Hardware the silicone,copper, other tangibles thatgenerate heat

Operating system arbitrates between multipleprograms and limitedresources

Figure : Notional view of computerlayers [3].

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Focusing on the OS

What does it do?

Provides a user interface(maybe a Command LineInterface)

Schedules access to thehardware

Schedules the functions ofthe CPU

Figure : A few OS details [2].

An OS is a program (albeit, a large program). What if we couldwrite a program that would run an OS as an application??

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Tricking the upper layer.

Higher layers rely on lowerlayers for services

Layers create interfaces

Interfaces allow for hidingdetails

What is real? And, what isvirtual? [1]

As long as the lower layer supplies all the services, the upper layerwont know where the services originated.

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One hardware suite can run many OS in virtualmachines.

Ultimately the hardwaredetermines how many virtualmachines can be run

Faster CPU(s), more RAM,more network connections,more disks, . . . , more isbetter

Fewer actual machinesusually means lower power,lower cooling, cheaperupgrade path

With clever software, almost anything can be virtualized. Hadoopis clever software.

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Anything that has to be fast.

Underlying hardware suite isshared across all machines

Mission critical applications

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In summary.

To use virtual machines, or

To not use virtual machines.

It depends on what is important.

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What have we covered?

There are lots of free virtualmachine programs for you totryThey are good for trying,testing, experimentingThey are good for maximumuse of available hardwareThey are not good forreal-time applicationsHDFS is a virtual file system

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References I

[1] Paul Hodge, Virtualization 101: Understanding how to do morewith less, https://www.isa.org/standards-and-publications/isa-publications/intech-magazine/2011/august/system-integration-virtualization-101-understanding-how-to-do-more-with-less/,2011.

[2] Willy-Peter Schaub,UNISA Chatter Operating System Concepts: Part 2 System Structureshttp://blogs.msdn.com/b/willy-peter schaub/archive/2010/01/07/unisa-chatter-operating-system-concepts-part-2-system-structures.aspx,2010.

[3] Wikipedia, Software Wikipedia, The Free Encyclopedia,http://en.wikipedia.org/wiki/Software, 2015.

How do programs operate?

What is Virtualization?

What is it good for?

What is it not good for?

Conclusion

References

"Chuck Cartledge"

ScheduleMiscellaneaCorrections and additions since last lecture.This and that

Chapter 5Conditions, logical expressions, and selection control structuresTesting

BreakTest preps.Some ideas

Hands onQ & AConclusionReferencesFiles

CSC-201 - Computer Science I Lecture #3: Chapter...

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