C language (Basic Element)

Basic Elements of “C”

^^lh** dks “kq: djus ls igys blds dqN vk/kkjHkwr vo;okas dks tku ysuk cgqr t:jh gSA dqN [kkl rjg dh Statements dks fy[kus ds fy, fofHkUu izdkj ds Operators o Expressions dh t:jr gksrh gSA gj Hkk’kk esa dqN [kkl Statements o mudks fy[kus ds dqN [kkl rjhds gksrs gSaA ;s gh ckr ^^lh** Hkk’kk ij Hkh ykxw gksrh gSA bl v/;k; esa ge ^^lh** ds vk/kkjHkwr vo;oksa ds ckjs esa tkusaxsA

 

“C” Characterset

izR;sd Hkk’kk esa fpUgks] vadksa] v{kjksa dk ,d lewg gksrk gSA bu fpUgks] vadksa o v{kjksa dks ,d fo”ks’k Øe esa j[kus ij ,d “kCn curk gS ftldk fd viuk ,d [kkl vFkZ gksrk gSA tSls j~ $ v $ e~ feydj jke “kCn cukrs gSa ftldk viuk ,d vFkZ gksrk gSA

blh rjg ^^lh** esa Hkh dqN [kkl fpUgks] vadks o v{kjksa dks ekU;rk nh xbZ gS] ftuds feyus ls dqN [kkl vFkZ fudyrs gSa ftUgs okLrfod rkSj ij flQZ dEI;wVj gh le>rk gSA bu fpUgks] vadksa o v{kjksa ds lewg dks ^^lh** Hkk’kk dk ^^lh** dsjsDVj lsV dgk tkrk gS] tks fd fuEukuqlkj gksrk gS%

 

1 Uppercase (A-Z) and Lowercase (a-z) Alphabet

2 0 to 9 Digits

3 Whitespace Characters (Blank Space, H-Tab, V-Tab, Form Feed, New Line Character, Carriage Return )

4 Special Characters

,	Comma		;		Semi Colon
:	Colon		?		Question Mark
.	Dot		'		Single Quote
"	Double Quote		|		V-Bar
$	Dollar Sign		#		Pound Sign
&	Ampersand		*		Asterisk
(	Left Parentheses		)		Right parentheses
[	Left Bracket		]		Right Bracket
{	Left Curly Brace		}		Right Curly Brace
<	Less Then Sign		>		Greater Then Sign
Blank		=		Equal to
\	Back Slash		/		Slash
_	Under Score		%		Percent
~	Tilde		^		Upper Carat
+	Plus		-		Minus
!			Exclamation mark

 

 

“C” Tokens

ftl izdkj ls “kCn] fdlh Hkh iSjkxzkQ dh og y?kqRre bdkbZ gksrh gS] ftlesa ,d fo”ks’k vFkZ fo/keku jgrk gS] Bhd blh rjg bl Hkk’kk esa Hkh ,sls gh dqN “kCn] fpUg vkfn gSa] tks Lora= :I ls viuk dqN vFkZ j[krs gSaA ^^lh** Hkk’kk dh og y?kqRre bdkbZ tks Lora= :i ls viuk dksbZ vFkZ j[krh gS] ^^lh** Vksdu~ dgykrh gSA ^^lh** Hkk’kk esa ikap rjg ds ^^lh** Vksdul~ gksrs gSa] ftUgs fuEukuqlkj le>k;k x;k gS%

 

Keywords ;k Reserve Words

^^lh** Hkk’kk ds dqN “kCnksa dks Reserve j[kk x;k gSA bu “kCnksa dk C Compiler ds fy, Special Meaning gksrk gS] blfy, bUgsa Keyword ;k Reserve Words dgrs gSaA gj Reserve Word dk viuk ,d Special Meaning gksrk gS vkSj gj Reserve Word dks fdlh fo”ks’k ifjfLFkfr esa fo”ks’k dke dks iwjk djus ds fy, gh Use fd;k tkrk gSA ge fdlh Reserve Word dks fdlh lkekU; dke ds fy, Use ugha dj ldrs gSaA C Hkk’kk esa fuEukuqlkj 36 Keywords Define fd, x, gSaA dqN Compilers esa budh la[;k 32 gh gksrh gS rks dqN Compilers esa budh la[;k 36 ls T;knk Hkh gks ldrh gSA

 

Identifiers – Constant and Variable Name

tc ge Program Develop djrs gSa] rc gesa fofHkUu izdkj ds Data dks Computer dh Memory esa Input djds ml ij fofHkUu izdkj dh Processing djuh gksrh gSA Computer esa Data ds lkFk ge pkgs fdlh Hkh izdkj dh izfØ;k djuk pkgsa] gesa gj Data dks lcls igys Computer dh Memory esa Store djuk t:jh gksrk gSA Computer dh Memory esa fdlh Data dks Store fd, fcuk ge ml Data ds lkFk fdlh izdkj dh dksbZ izfØ;k ugha dj ldrs gSaA

Computer esa Memory ds gj Location dk ,d Unique Address gksrk gSA tc ge Computer esa fdlh Data dks Process djus ds fy, Input djrs gSa] rc og Data Memory ds fdlh uk fdlh Location ij tkdj Store gks tkrk gSA

ysfdu gesa dHkh Hkh lkekU; rjhds ls ;s irk ugha py ldrk gS fd gekjs }kjk Input fd;k x;k Data Computer dh fdl Memory Location ij Store gqvk gS vkSj uk gh ge Lo;a dHkh ;s r; dj ldrs gSa fd gekjk Data fdl Memory Location ij Store gksxk] D;ksafd Data dks Memory Allocate djus dk dke viuh lqfo/kkuqlkj gekjk Operating System Lo;a djrk gSA

ftl le; gekjs Data dks Store djus ds fy, Compiler Memory Reserve djrk gS] mlh le; ge ml Reserve gksus okyh Memory Location dk ,d uke Assign dj nsrs gSaA bl uke ds }kjk gh ge gekjs Data dks Computer dh Memory esa Identify dj ldrs gSaA gekjs }kjk fdlh Data dh Memory Location dks fn, tkus okys bl uke dks gh Identifier dgrs gSaA

ge fdlh Memory Location dk tks uke Assign djrs gSa] mu ukeksa dks dqN fu;eksa dks /;ku esa j[k dj ifjHkkf’kr djuk gksrk gSa] D;ksafd ^^lh** dEikbyj mu fo”ks’k izdkj ds fu;eksa ds vk/kkj ij ifjHkkf’kr fd;s x, ukeksa ds lkFk gh fofHkUu izdkj dh izfØ;k,a djrk gSA fdlh Identifier dks uke nsus ds fy, gesa fuEu fu;eksa dks Follow djuk gksrk gS] ftUgsa Identifier Naming Convention dgk tkrk gS%

• fdlh Hkh Identifier ds uke esa fdlh Hkh Upper Case o Lower Case Character dk iz;ksx fd;k tk ldrk gSA

• fdlh Hkh Identifier ds uke esa Underscore dk Hkh iz;ksx fd;k tk ldrk gSA

• fdlh Hkh Identifier ds uke esa ;fn ge vadksa dk iz;ksx djuk pkgsa] rks vadksa dk iz;ksx djus ls igys de ls de ,d Character ;k Underscore dk gksuk t:jh gksrk gSA

• blds vykok Identifier ds uke esa fdlh Hkh izdkj ds Special Symbol tSls fd Period, Comma, Blank Space vkfn dk iz;ksx ugha fd;k tk ldrk gSA lkFk gh ge Identifier ds uke esa fdlh Reserve Word ;k fdlh Built-In Function ds uke dk iz;ksx Hkh ugha dj ldrs gSaA

• fdlh Hkh uke dh “kq:vkr fdlh vad ls ugha gks ldrh gSA

• ^^lh** ,d Case Sensitive Language gS] blfy, bl Hkk’kk esa Capital Letters o Small Letters ds uke vyx&vyx ekus tkrs gSaA tSls int Sum o int sum nks vyx&vyx Variable Name ;k Identifies gksaxs uk fd lekuA

 

Constants and Variables

 

Constants

fdlh Hkh Computer Program esa ge fofHkUu izdkj ds ekuksa dks Computer esa Store djrs gSa] mUgsa Manage djrs gSa] mu ij Required Processing Apply djrs gSa vkSj muds ifj.kke dks Output esa izkIr djrs gSaA ;fn ge Real World esa ns[ksa rks nks rjg ds eku gksrs gSaA ,d eku os gksrs gSa ftUgsa dHkh Change ugha fd;k tkrk gSA

 

Variables

Program ds os eku tks iwjs Program esa le;≤ ij vko”;drkuqlkj cnyrs jgrs gSa] Variables dgykrs gSaA Variables dHkh Hkh fdlh fLFkj eku dks Represent djus ds fy, Use ugha fd, tkrs gSaA tc Hkh gesa fdlh Constant dks Program esa Use djuk gksrk gS] rks ml Constant dks Represent djus ds fy, gesa Symbolic Constants dh t:jr gksrh gSA bu Symbolic Constants dks gh Literal Hkh dgk tkrk gSA