Learn Tiny Bit of C# in 7 days-Day1

8/18/2019 Learn Tiny Bit of C# in 7 days-Day1

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Learn C# in 7 Days – Day 1

Introduction: As the title specifes “Learn C# in 7 days” I will be writin

article !or the sa"e the intended !ocus is towards the beinners so that they

can easily rasp the C# Lanuae concepts and beco"e C# de$eloper a!terreadin the articles% &o let's et started with Day 1% In case you !eel I ha$e

le!t the $ery i"portant topic !eel !ree to co""ent and any correcti$e

"easures and i"ple"entation are "ost welco"ed%

Day1 Contents

1% Introduction(% Aenda)% Creatin *our +irst ,rora"-% Console ,rora"s.% /scape &e0uencin

% /2ceptional 3andlin7% Arrays4% +or /ach Loop5% ,arallel%+oreachLoop


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Introduction

C# is ob6ect oriented prora""in lanuae which allows us to build

lare $ariety applications% It was de$eloped by icroso!t within %8/9

!ra"ewor% C# is one o! the "any lanuaes that are supported by

%8/9 !ra"ewor% Its de$elop"ent tea" is led by Anders 3e6lsber% 9he

Current $ersion is C# %; which was released on isual &tudio you can download !ro" the

below lin https:www%$isualstudio%co" %Step2. Create New Project Clic! on File"# New"# Project

https://en.wikipedia.org/wiki/Anders_Hejlsberghttps://www.visualstudio.com/https://www.visualstudio.com/https://en.wikipedia.org/wiki/Anders_Hejlsberg


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Step$% Select Visual C& *ou can see the !ollowin set o! options a$ailable with >isual C# usin

these co"ponents we can de$elop our respecti$e applications%


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Biht now we will select Console 'pplication and na"e our ,ro6ect as

C&harp&tepy&tep% ?e will i"ple"ent the C # concepts usin Console

'pplication because it si"plifes the learnin process o! C#% @nce the

loadin o! classes and re0uired co"ponent need !or $isual studio pro6ect et

loaded we will ha$e our ,rora"%cs fle as shown below:

usin &yste"usin &yste"%Collections%Eenericusin &yste"%Lin0usin &yste"%9e2tusin &yste"%9hreadin%9ass

na"espace C&harp&tepy&tepF class ,rora" F static $oid ainGstrinH arsJ F

K KK

I will be ettin rid o! little code as it's our frst war" up topic I don't want

you to "ess up and con!use% In short I will only eep the code that is

necessary%

usin &yste"

class ,rora" F static $oid ainGJ

F

K K

8ow you can see I ha$e re"o$ed so"e code that will tal in our later section%

&o now I want to print ?elco"e to Learn C# &tep y &tep in Console window%

y console window I "ean to say is Command Prompt% &o in order to do

that I will 6ust write Console.(rite)ine*+message,-. % 3ere Console is a

class% ?riteLine is used to write the "essae or data to the screen or the ser%Console%Beadline is used to tae input !ro" the ser until and unless user presses the

input !ro" the eyboard the screen waits !or the input%

usin &yste"

class ,rora" F static $oid ainGJ F Console%?riteLineGMLearn C# &tep by &tepMJ K


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K

&o once I run "y application in debu "ode the co""and window 6ust pops up and ets closed

in order to eep the window open we use one "ore "ethod o! Console called Beadey which will

not close the console window until and unless the user presses a ey or you can run the prora"

usin ctrlN!. run without debuin%

usin &yste"

class ,rora" F static $oid ainGJ F Console%?riteLineGMLearn C# &tep by &tepMJ Console%BeadOeyGJ K K

Let's !ocus little in depth !or the abo$e code to understand it better%

sing Sytem%

9his line sinifes that in our prora" we are oin to "ae use o! &yste"

8a"espace% &o you "iht be thinin what the hell 8a"espace is%

Namespace is a collection o! classes when we use our Console%?riteLine or

Console%BeadLine you "ay ha$e seen the !ollowin

9hat speci!y the Console class is present in the &yste" 8a"espace i! we

re"o$e the sin &yste" 8a"espace we would et co"pile error

9hat "eans co"piler don't now where do Console e2ist% ?e can add the

!ully con$entional eyword &yste"%Console class na"e be!ore usin its

!unction as shown below


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class ,rora" F static $oid ainGJ F &yste"%Console%?riteLineGMLearn C# &tep by &tepMJ &yste"%Console%BeadLineGJ K

Kut doin this we ha$e to use &yste" where$er we want to use the Console Class in order to use&yste" class so in order to a$oid this we use the" at top in sin &ection%

/$ery lines o! Code should be inside a Class we will discussin about class

once we o ahead%

class ,rora" F static $oid ainGJ F &yste"%Console%?riteLineGMLearn C# &tep by &tepMJ

&yste"%Console%BeadLineGJ KK

Static Void /ain*-

0s an entry point unction wic tells te compiler rom were te e3ecution is going

to start.

Once te program get e3ecuted it4s enter te entry point unction and e3ecute te

sets o instructions.

56ip7 (en you want to see te 8ow o program you can insert a 9rea!point using F:

and see your program 8ow line 9y line.

Console ,rora"sIn this topic we will be enhancin our frst prora" by tain input

!ro" the ser and displayin the desired results to the ser%As we ha$e learnt to write to Console we write Console%?riteLine so

when we want to read the ser Input we use Consol%BeadLineGJ 9his


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!unction reads the ne2t lines o! characters !ro" the standard input

strea" as shown abo$e in fure% In order to read the ser Input we

ha$e to read the ser Input in a $ariable 5note $ariable is a location in

"e"ory which is used to store data used in Application% @nce the

$alue is stored in $ariable we will display the ser entered $alue

concatenated with to Learn C #&tep by &tep as shown below:

usin &yste"

class ,rora" F static $oid ainGJ F Console%?riteLineGMLearn C# &tep by &tepMJprintin to the Console Console%?riteLineGM/nter your 8a"eMJprintin to the Console strin ser8a"e P Console%BeadLineGJBeadin ser Input Console%?riteLineGM?elco"e MNser8a"eN M to Learn C# &tep by &tepMJprintin user

entered concatenated with other strin% Console%BeadLineGJ

K

K

Let o throuh code

As we can see that Console%?riteLine has been printed to the console

?indow now yellow shaded lines read the ser Input stores it into

$ariable called ser8a"e and in ne2t line we write the $ariable $alue

alon with strin as shown below%


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C& is a case sensiti;e language i.e.

9he word Case sensiti$e "eans the te2t is sensiti$e to capitaliQation o!letters or words% e2%Class and class are two diRerent word because o! C o! frst bein Caps% *oucan see the below fure !or "ore elaboration%

added

>ariable

Is the s"all "e"ory data which are allocated to our prora" where actual data will be stored%

In below e2a"ple we are usin a &trin $ariable to tae the input !ro" the ser and display the

sa"e to the screen%

usin &yste"

na"espace readlineF class ,rora" F static $oid ainGstrinH arsJ F Console%?riteLineGM/nter your 8a"eMJ strin user8a"e P Console%BeadLineGJ Console%?riteLineGM*our 8a"e is F;KMuser8a"eJ


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Console%BeadOeyGJ

K KK

Console%?riteLineGM*our 8a"e is F;KMuser8a"eJ

3ere we are concatenate “ *our 8a"e is” and user8a"e $alue

IntLet tae up that we ha$e another re0uire"ent o! Ae as we all now that ae is aninteer type% &o we ha$e to tae inteer as a $ariable% ?hen we try to read the

input !ro" the ser as shown below the error appears

As the error specifes cannot con$ert strin to a inteer whene$er we tae input

!ro" the user it's is always treat as a strin so we need to con$ert it to our re0uired

datatype%

usin &yste"

na"espace readlineF class ,rora" F static $oid ainGstrinH arsJ


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F Console%?riteLineGM/nter your 8a"eMJ strin user8a"e P Console%BeadLineGJ Console%?riteLineGM/nter your aeMJ int userAe PCon$ert%9oInt1G Console%BeadLineGJJ Console%?riteLineGM*our 8a"e is F;K and your ae is F1KMuser8a"euserAeJ Console%BeadOeyGJ

K KK

9he output o! the prora" i! users inputs correct inteer $alue%

8ow i! I try insertin the nonSinteer $alue I will !ace an e2ceptionerror as shown

below “Input strin was not in a correct !or"at”% &o now to learn about /2ceptional

3andlin we will learn ahead in this article%

added

/scape &e0uencin&o"eti"es we need to add Character co"binations consistin o! a bacslash

GTJ !ollowed by a letter in our prora"s e% ?e want our output to ha$e been


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lie this +


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&o in order to do /2ceptional 3andlin we need two thins%

9ry Catch and fnally we can see in abo$e fure !ro" where our /2ception

was raised or prora" crashed% &howin the actual unhandled e2ception will

annoy the user as they are cryptic and do not "ae sense to the end user%

?e can tell the co"piler that I a" e2ceptin to et error in this line and in

case you et e2ception can you 6ust throw the /2ception into the Catch as

shown below%

usin &yste"

class ,rora" F static $oid ainGJ F int a P 1; int b P ; int result try F

result Pab Console%?riteLineGMTn Besult a!ter di$ision is MresultJ Console%BeadLineGJ K catchG/2ception e2J F Console%?riteLineGMDi$isor should be reater than ;MJ Console%BeadLineGJ K

K

K

/2ception is actually a class that deri$es !ro" &yste"%/2ception class% ?ith

the help o! this we can show the ser +riendly "essae to the sers rather

than Co"piler "essae shown by the co"piler%


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An e2ception Class has se$eral use!ul properties Gwe will learn "ore about

properties as we o aheadJ that pro$ide $aluable in!or"ation about the/2ception%

• essae: Describes the current e2ception details

• &tac9race: ,ro$ide the call stac to the line nu"ber in the "ethod

where the e2ception occurred%

?hat i! rather than usin /2ception class we use Di$ideyUero/2ception which isa child class o! /2ception% &yste"%/2ception is base class o! /2ception

• Di$ideyUero/2ception Inherits !ro" Arith"etic/2ception

•

Arith"etic/2ception Inherits !ro" &yste"/2ception• &yste"/2ception Inherits !ro" /2ception

8ow usin Di$ideyUero/2ception

catch GDi$ideyUero/2ception e2J F

Console%?riteLineGMDi$isor should be reater then ;MJ Console%?riteLineGe2%Data%9o&trinGJJ Console%?riteLineGe2%essae%9o&trinGJJ Console%?riteLineGe2%&tac9race%9o&trinGJJ Console%BeadLineGJ

K


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ut this catch bloc will only handle Di$ideyUero/2ception so in order to

catch other /2ception we can include another catch bloc and use base

e2ception type as shown below%

8ow I a" tryin to read the content o! the fle and i! any e2ception occurs

while readin the sa"e e2ception will be handled $ia /2ception class else i!

while di$idin we et di$ide by Qero /2ception that will be handled by

Di$ideyUero /2ception class%

usin &yste"usin &yste"%I@

class ,rora"

F static $oid ainGJ F int a P 1; int b P ; int result try F &trea"Beader ob6 P new &trea"BeaderGVMC:TsersTDe$eloperTDocu"entsTArticleT%net+ra"eworT,roduct OeMJ Console%?riteLineGob6%Bead9o/ndGJJ ob6%CloseGJ

result P a b

K catch GDi$ideyUero/2ception e2J F

Console%?riteLineGMDi$isor should be reater than ;MJ Console%BeadLineGJ K

catch G/2ception e2J F

Console%?riteLineGe2%essae%9o&trinGJJ Console%BeadLineGJ

K

K

K


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+inallyS here the set o! state"ents are written that you want to e2ecuteirrespecti$e o! /2ception occurs or not% /% Disposin AD@%8/9 ob6ects Close

I@ ob6ects etcGW8ote we will be discussin these topics aheadJ% +inally bloc

is not "andatory%

In abo$e code as soon as the /2ception occurs the handle is trans!erred to

the /2ception class nelectin all other state"ent a!ter that that would

result in ob6ect occupyin the "e"ory% &o in order to close the sa"e we will

do it in fnally bloc as shown below%


class ,rora" F static $oid ainGJ F int a P 1; int b P ; int result &trea"Beader ob6 P null try F

ob6 P new &trea"BeaderGVMC:TsersTDe$eloperTDocu"entsTArticleT%net+ra"eworT,roduct OeMJ Console%?riteLineGob6%Bead9o/ndGJJ

result P a b

K catch GDi$ideyUero/2ception e2J F Console%?riteLineGMDi$isor should be reater then ;MJ

K

catch G/2ception e2J

F

Console%?riteLineGe2%essae%9o&trinGJJ

K

fnally

F i! Gob6XPnullJ


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Fob6%CloseGJ

K Console%?riteLineGMI a" fnally blocMJ Console%BeadLineGJ

K

K

K

Inner /2ceptions@nce while e2ecutin our ,rora" we !ace so"e e2ception so we handle the

e2ception in catch bloc what i! we want to do so"e operation inside catch

bloc !or e% ?ritin e2ception to a te2t fle etc% In order to do these

operations we "ay !ace so"e other Inner /2ception inside a catch bloc so

let's see how we handle the Inner /2ceptions% 8ow as I ha$e "entioned I

want to lo the /2ception to a te2t fle with e2ception "essae trace and

data and ti"e%


class ,rora" F static $oid ainGJ F int a P 1; int b P ; int result

try F

result P a b

K

catch G/2ception e2J


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F

strin +ilepath P VMC:TsersTDe$eloperTDocu"entsTArticleT%net +ra"eworT/2ception%t2tM i! G+ile%/2istsG+ilepathJJ F &trea"?riter ob6/2ception P new &trea"?riterG+ilepathJ ob6/2ception%?riteGDate9i"e%8owNM MNe2%essaeNM MNe2%&tac9raceJ

K

else F throw new +ile8ot+ound/2ceptionGM+ile not !ound MN +ilepathe2%essaeJ K

Console%?riteLineGe2%essae%9o&trinGJJ

K

K K

*ou can see in abo$e code that once the Di$ide by Uero /2ception co"es I a" writin the

e2ception to te2t fle as shown below

?hat i! while writin the /2ception I !ace another e2ception so in order to handle that we use 9hrow /2ception as shown abo$e%

Arrays


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Array is a roup o! si"ilar data types /% I we want to store 1; inteers% As

this article is !ocused on C# I will not be oin in depth o! Arrays% I will help

you how to declare and use Arrays in c#%

&ynta2 o! Declarin an Array

intH int'rr P new intH) siQe to specifed Gna"e o! arrayJ

/:


na"espace ArraysF class ,rora" F static $oid ainGstrinH arsJ F intH intArr P new intH1;

!or Gint i P ; i Y 1; iNNJ loopin threw I and assinin I $alue to array F intArrHi P i K Console%?riteLineGM9he Arrays consist o! !ollowin $aluesMJ !orGint iP;iY1;iNNJ F Console%?riteLineGintArrHiJ K Console%BeadLineGJ


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K KK

Ad$antaesS

• Arrays are stronly typed they don't allow storin other data type apart !ro"

declared data type%

• (D arrays are used to represent "atrices.

+i 1: Arrays are stronly typed i%e% it can only accept the $alue o! declared datatype%

Disad$antaesS

• @nce we declare the array siQe it cannot be chaned%

• &ince the array siQe is f2ed so i! insert less $alue the "e"ory is wasted and

"ore than &yste"%Inde2@ut@!Bane/2ception will happen%

+oreach Loop

+or each loop is used to iterate threw the collection doesn't includes initialiQationter"ination and incre"entdecre"ent characteristics as in other loops%

Ad$antaes:


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• 8o need to now the siQe o! the Collection%

• Loops are easier to write it least error prone loop%

5Note Code &nippet !or !oreach Loop is !oreach and then press tab%

/2:

&ynta2: !oreachGdatatype sa"e a collection Datatype na"e in CollectionJFstate"entsK


na"espace ArraysF

class ,rora" F static $oid ainGstrinH arsJ F intH intArr P new intH1; creatin a collection o! int array !or Gint i P ; i Y 1; iNNJ F intArrHi P i K Console%?riteLineGM9he Array consist o! !ollowin $aluesMJ

intArr is a collection!oreach Gint >alue in intArrJ

F

Console%?riteLineG>alueJ K

Console%BeadLineGJ

K KK


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Fig% Demonstrating ow 'ctually For >ac )oop Flows

's we mo;e aead we learn more 9ene?ts o using or eac loop.

Parallel Foreac)oop0n .net /icrosot@ .N>6 Framewor! A /icrosotpro;ide Parallel Computing eatures wicspeci?es new programming wor!ing model orwriting multi7treaded and asyncronous code . 0won4t 9e going in dept o tat and will ocus onParallel Foreac)oop gi;en in Parallel Computing.'s we a;e learn a9o;e a9out Foreac loop we alsoa;e Parallel oreac loop. 0n seBuential oreacloop te loop is run rom single tread wile inParallel Foreac loop it uses multiple treads. 6eimplementation o Parallel Foreac loop sould 9edone wen we a;e our independent set o

https://msdn.microsoft.com/library/ms171868(v=vs.100).aspx#parallel_computinghttps://msdn.microsoft.com/library/ms171868(v=vs.100).aspx#parallel_computing


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statements i.e. not depending upon eac oter.6e parallel loop runs aster wen te computeras a;aila9le cores.

Conclusion3ere we co"plete our day 1% In day 2 we will talk about Namespaces, Classes,

Inheritance, Access Modifiers, Properties, Interface and Abstract Class. So keep readin, keep

learnin.

I! any con!usion you can co""ent !or the sa"e% Any !eedbacs and added

in!or"ation is heartily welco"ed%
https://www.youtube.com/watch?v=IQTbvVemMAg&list=PLAC325451207E3105&index=18https://www.youtube.com/watch?v=Us2i7D-urgs&list=PLAC325451207E3105&index=19https://www.youtube.com/watch?v=Us2i7D-urgs&list=PLAC325451207E3105&index=19https://www.youtube.com/watch?v=OLTk0xAVY00&list=PLAC325451207E3105&index=21https://www.youtube.com/watch?v=OLTk0xAVY00&list=PLAC325451207E3105&index=21https://www.youtube.com/watch?v=IQTbvVemMAg&list=PLAC325451207E3105&index=18https://www.youtube.com/watch?v=Us2i7D-urgs&list=PLAC325451207E3105&index=19https://www.youtube.com/watch?v=OLTk0xAVY00&list=PLAC325451207E3105&index=21https://www.youtube.com/watch?v=OLTk0xAVY00&list=PLAC325451207E3105&index=21

Learn Tiny Bit of C# in 7 days-Day1

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