Today I will discuss short summary of C Language which i have analysed till now for those who want to revise basic concepts.
\nThere are two compilers which are known to me to compile C Programs.Turbo C Compiler and Quick C Compiler.Small Change in
\nLibrary fuctions of Turbo C Compiler can give birth to Quick C Compiler.C is basically used to connect user with computer
\nhardware like ROM, RAM, BIOS and Harddisk in IBM compatible computers with MS-DOS OS.The basic objective to use C Language is
\nto know different methods to input and output data of user and to combine and manipulate data.<\/p>\n
C was created by Dennis Riche in 1972 after the fall of PASCAL, FORTRAN, PL\/I, ALGOL Languages.After Creation of BCPL and then
\nB language by Ken Thompson C came into existence in AT & T Bell labs USA.Sab Kuch Usa mein hi bana hai kya.Language do tarah
\nki hotee hain.High level , jo humarey program designing ko fast karti hain. Jaise Fortran, Pascal aur Low level jo program
\nexecution ko fast karti hai jaisey TASM, ASM.Lekin C mein yeh dono khubian hain.Sabse pahley Commercially COBOL use hotee thee
\naur scientific & mathematical calculations ke lie FORTRAN use hotee thee.Lekin dono ko mila kar ALGOL60 bana di gayi jo ki
\nasaani se samajh nahi aati thee, iseley CPL banai , lekin usme bhi bahut saarey features thee jinhey dhoondna mushkil ho jata
\ntha….isley ant mein BCPL banaai.
\nAb hum C ka Character set dekengey bhai… kehney ka matlab hai ki C ka program kin kin cheezon se mila kar bantaa hai.Constant
\n,Variable aur Keywords kya hotee hain? Constant jaisey 2,3 values hotee hain, jinko change nahi kiya jata…jabki variable ko
\nchnage kar saktey hai aur Keyword jinka matlab pahley se hi library mein define kiya hua hai …. bas hum key keword likh dete
\nhain aur program apney aap sab kuch samjh jata hai.Dekh Bhai , tu keyword ko apney naam ya kisi aur word se replace nahi
\nkar saktaa kyonki wo pahle se hi defined hai….samjha ya samjhi?Constants Int Real aur char type ke hotey hain.Int jo without decimal
\nnumbers hotey hain , Real jo decimal waaley hotey hain aur char constants jo single inverted comma “‘” mein likhe jaatey
\nhain, jinkey ASCII value le jaati hai.If, else, break, while yeh saare keywords hain jo pahley se defined hain.Samjha bedu.
\nAb instructions ke baarey mein baat kartey hain jo in sub ko mila kar bantee hai.Instruction type bataaney ke lie, arithmatic
\ncalculations ke lie, input\/output karney ke lie aur programm ke sequence chnage karne ke lie use hotee hain.Agar mein a+b=c
\nliktaa huin to yahaan par a,b operands hain, aur + operator.
\nSequence change karne ka matlb hai ki pahley program ki kisi aur line ko execute karnaa aur phir pahli ya doosri line ko.
\nHumney if, for, while loop padey hain, jinkaa indentation right side ko khisktaa jata hai hai … aisaa hogaa to program
\nright hand side ko shift hotaa jaaega…. isley hum Logical operators ka use karte hain jaise AND,OR or NOT.Isey loop ki
\ninstruction choti ho jaatee hai… samjh le be… Koi nahi bataaegaa
\nAgar mein if (i=5) {work();}; use karta huin to, work to work();chalegaa hi kyonki i=5 ek positive aur true value hai, jo
\nstatement ko execute kargee hi
\nif(i==2)
\nstatement 1;
\nstatement 2;
\nAgar statment 2 bracket mein nahi daali to yeh if condition se bahar ho jaaegi aur humsha execute hogee hi kyonki if ke
\nlie to pahli statement 1 hi maani jaaegi.Loop se bahar aaney ke lie break use hotaa hai.
\nwhile(i++ <= 31000);
\nyahaan i ki value range se bahar jaa rahi hai, isley indefinite loop chalegaa.Indefinite loop ko avoid karney ke lie
\ncounter increment jaroor karein.Is statement mein pahley comparison hoga aur phir increment.Pad lo bhai.
\nProgram se bahar aaney ke lie exit() use hotaa hai.Switch mein har case ke baad break; jaroor lagaa lenaa nahi to saaree
\nstatements execute ho jaaengi…phir puneet ko mat bolnaa ….meraa farz thaa bataana
\nFuctions ke baarey mein batata huin Called function mein jo arguments hotey hain, wo actual hotaa hain.Aur jahaan fuction
\nlikkha hota hai , wahan ke argument formal argument hotey hain.Float value main me called function mein return karney ke
\nlie fuction se pahle float laga do.Har function ke variables ki value usee function tak local rahti hai… isley hum values
\npass karte hain.Kisi function mein function nahi likhaa jata aur execution hamesha main() se start hotaa hai.Return; statement
\ngarbage value return karegi.do varibales ki value ko swap aur adlaa badlli karney ke lie call by reference use hota hai, jimey
\nhum pointers ka use kartey hain.Varables ko memory mein 4 tarah se store kiya jaa saktaa hai
\n1.Auto – default hota hai … lagaao ya nahi … initial value garbage hotee hai
\n2.Static – Value humesha jindaa rahti hai… ek function se doosrey function mein transfer hotee hai – initial vaule=0
\n3.Register – fast processing ke lie counter variable mein use hotey hain, initial = garbage
\n3.Extern – variable har function mein use kiya jaa saktaa hai globally, initial = 0;<\/p>\n
Data types:
\nint 2 byte ka hotaa hai aur char ek byte ka
\n4 byte ka int long int ho jata hai
\n4 byte ka float hota hai
\n8 byte ka double
\naur 10 byte ka long double
\nagar signed hai to ek sign bit bhi hogi 1(-ve) or 0(+ve)
\nInt ki range -+32700
\nchar ki range -+127
\nrange se bahar honey par indefinite loop chalega
\nunsigned +127 + 127 = 0->+255<\/p>\n
Macros define kaisey kartey hain.Preprocesor source code ko expanded source mein convert kar detaa hai<\/p>\n
main(); se pahley<\/p>\n
# define PI 3.14<\/p>\n
PI template hai
\n3.14 macro expansion hai
\nJiasey “\\X1B[2]” command ke jagah hum Clearscreen template use kar saktey hain pooray program main.Bor to nahi ho raha?<\/p>\n
Isi tarah (n*n) macro ki jagah hum SQUARE(n) Template ka use kar sakte hain after defining before main().
\nchotey macros program ko fast kaartee hain bjaai ki fuctions se values caal karaaney se
\n#include “goto.c”
\nLibrary + Current Directory = dono mein khoj hogi<\/p>\n
#ifdef OKAY
\nstatemnt 1;
\n#endif statement 1 tabhi chalegi jab Okay macro define hoga main se pahley<\/p>\n
ARRAY
\na[1] = 6;
\na-> subcripted variable hai
\n1-> subscript hai
\narray ki values jab sequncially access karni ho, to subscript ki jagah pointer ka use karnaa chahiye … pahley subscript
\nke address pe pointer set kar do, aur pointer ko loop se aagey badaatey jaao<\/p>\n
a -> base address of a
\na+1 -> next address
\n*(a+1) -> value at a+1
\na[0] -> value at base address
\na[0]+ 0 -> value at base address
\na[0]+ 1 -> value at next address<\/p>\n
Array of Characters —> Strings —> Puppeting<\/p>\n
char name[] = {‘P’,’U’,’N’,’E’,’E’,’T’,’\\0′};
\nset pointer ptr at name[0]
\nptr = name;
\nand start incrementing ptr++ till null ‘\\0’
\nPuneet ko arrary name mein daal rahein hain aur phir base address pe ptr pointer set kar ke, pointer ko aagey le ke
\njaa rahey hain jab tak null char nahi aaa jata…. hee heee heee neend aaa rahi hai kya ? so gaye kya ? uth jaao beta<\/p>\n
<\/p>\n
scanf(); –> ek hi word ka string input karaa saktey hain
\ngets(); –> multi word string bhi kara sakte hain
\nputs(); –><\/p>\n
Humseha ‘\\0’ jaroor place karnaa chahiye source string se target string mein copy maarney ke lie
\nstrcpy(); automatically null assign kar detaa hai.<\/p>\n
STRCMP — 2 strings ko compare kareingey
\nPuneet
\nPuneet
\n————
\n000000 ASCII values … dono ka difference 00000 hai, isley string match kar rahein hain<\/p>\n
Puneet
\nSuneet
\n——-
\n4 ASCII value 0000 nahi hai …. mismatch ho gaya
\n——-<\/p>\n
Puneet
\nPuneet-ji
\n———-
\n-32 kyonki null mein se ghtaa rahe hain hum….. samjaa……. again mismatch ho gaya
\n———-<\/p>\n
<\/p>\n
Hum ek 2d array names[4][12]
\nlete hain aur usmey<\/p>\n
01234567890(11)(12)
\n0.Puneet- – – – –
\n1.Puneet Verma- –
\n2.Puneet Ji- – –
\n3.Puneet webmaster<\/p>\n
to humney dekhaa ki kasey iss 2d array main kaafi memory unused rah gayi strings ke beech mein, jahaan _ _ _ blank
\nlagey hain<\/p>\n
Iss memory ko bachaaney ke lie hum Array of pointers use kartey hain kyonki pointer base har row ke base address pe
\npoint karega aur last location 4×12= 48 ki bajaaey 4 ho jaaegi.Yahan sirf har row ke base address ko store karne
\nke lie memory use hogi aur _ _ _ blanks waali memory bach jaaegi<\/p>\n
Yahah hum memory ka efficenct use kar paa rahey hain … aur changes karnaa aasaaan ho jaaegaa<\/p>\n
Yaad rakhio … hum kabhi bhi array pointers ko keboard se nahi le saktey ya scanf nahi karaa saktey<\/p>\n
SRUCTURES
\nAlag Alag datatypes , jaisey int char float ka collection se structure bantaa hai… aur ek structure ko hum
\nkai objects ke lie use kar sakte hain.
\nJaisey ek book naaam ka structure banaa liaa , aur humney 100 books ke information ke lie 100 structures kaa
\nmemory define kar diya.
\nstruct book
\n{elements};
\nstruct object b[100];<\/p>\n
Array mein elements ki jagah bahut saarey structures bhi daal sakte hain …… jisey similar data type
\ncollecttion structures ka hoga, jo ki dissimilar data types ka collection hotey hain<\/p>\n
Array {
\nsimilar data typtes like
\nstruct 1 {dissimilar data types}
\nstruct 2 {dissimilar data types}
\nstruct 3 {dissimilar data types}<\/p>\n
}<\/p>\n
elements humesha ek ke baad ek contagious memory locations mein store hotey hain.<\/p>\n
Structures mein bajaai ki ek ek data element copy karney ke, hum variables ya objects ek doosray mein directly
\ncopy kar saktey hain.<\/p>\n
object2 = object1; (dekho aisey)<\/p>\n
structures ke objects ke nesting bhi ki jaa saktee hai
\nobject1.object2.object3 (is tarah se)<\/p>\n
Normally hum object1.name jasey actual arguments pass karaatey hain , aur char pointer<\/p>\n
Char *s as a formal argumant access kar lete hain.
\nLekin yeh kaam hum object1 pass karaa kar aur struct book object jasey formal argument ke form mein bhi le saktey hain<\/p>\n
Display(object1); ——> call<\/p>\n
Display(struct book object) ——> called function yahan humey struct globally define karnnaa padegaa taki called func
\nusey samajh sakey.<\/p>\n
Hum structure pointers ka bhi use kar saktey hain
\nptr = &object1;
\nDisplay(&object); ——–> Call<\/p>\n
Display(Struct book *ptr) ——>Called function
\n{ ptr->name printf karaa saktey hain}<\/p>\n
INPUT\/OUTPUT IN C
\nc mein input output functions ka development nahi hua tha , balki usey compiler developers ne banaya aur library mein daal dia<\/p>\n
I\/O functions ka use hum
\n1.Console(keyboard) se input dekar VDU par output lekar kar saktey hain
\n2.keyboard se disk par print kar saktey hain
\n3.Keyboard se port par output lene ke lie kar saktey hain<\/p>\n
Console inputs type do tarah se ho saktey hain
\n1.Foramt – jo print output ko idhar udhar shift karney ke lie use kar saktey hain … jaisey %10d right shift kar dega
\n%-10d left shift kar dega , us output ko jo screen pe nazar aaegaaa<\/p>\n
screen 80 column se milke banti hai aur ek tab 8 columns ke hotee hai….. aur symbols jaisey ‘ ko print karaaney ke lie
\npahley \\ lagaa saktey hain. Screen 10 tabs mein poori hotee hai …. mazaa aa raha hai naa ? mughey pataa tha …tabhi to
\ntu yahaan maze se C seekh raha hai…. soch meri kitnee waat lagi hogeee …. but u know mein india se bahut pyar kartaa
\nhuin……aur shyad tu bhi<\/p>\n
2.Unformat –> putch, puthcar,fputchar are examples<\/p>\n
Sprintf se string mein alag alag variables ke values daal sakte hain
\nSscanf se string se values lekar different variables mein daal saktey hain<\/p>\n
Unformatted functions jaisey getch or getche mein input dekar enter key nahi dabaani padti or getche mein input print ho
\njata hai , lekin getchar mein enter dabana padtaa hai aur input screen par aa jata hai …. for exampe yes or no option
\nke baad enter dabana padtaa hai<\/p>\n
Gets or puts se hum multi word string le saktey hain aur print karaa saktey hain.<\/p>\n
Input output functions with buffer manager and without buffer manager bhi hotey hain…. low level functions main
\nbuffer management apney aap hotaa hai… jabki high level mein programmer manage kartaa hai…… data text ya binary
\nformat mein store hota hai ……. text form mein kartey hain to ek ek char ek ek byte letaa hai … lekin binary mein
\nsab kuch asii value pe depend kartaa hai , aur space kam use hotaaa hai.<\/p>\n
Program se oS pe store koi file kholney ke lie hum FILE(size,location,pointer addr) structute ka use kartey hain aur
\nfile chotey chotey hisson mein memory mein load hoti rahti hai jab ak 27 naa aa jaaey ya EOF naa aaa jaaey….lols<\/p>\n
Ek variable ch ki help se hum data ek file se uthaa kar fputc kar dete hain doosri file mein aur fir usko fgetc se read
\nkar lete hain….. ch buffer ke tarah kaam karega … aur agar bffer poora nahi bharaa to process close karney ke lie
\nfclose func kaa use karengey.<\/p>\n
Ek exe file tyarar ho jaati hai…. jisey hum command line mein direct chlaa saktey hain…. lekin command line
\ntips kaa use karkey hum us exe file ko bahut saarey tareekon se use kar saktey hain, jaisey<\/p>\n
argv[0] argv[1] argv[2] ya filecopy pr1.c pr2.c ko hum command promt pe use kar rahey hain<\/p>\n
argv waaley program mein fs pointer jahaan per hai wahaan se data read hona shuru hoga or ch buffer mein aaa jaeyga
\n… phir jab tak ch EOF nahi ho jata ……. data fputc hotaa jaaega us location pe , jahaan ft pointer hai.<\/p>\n
Enter press kartey hi multi word string ya ek line fputs hogi ya enter hogi … agar ek baar enter press karney ke
\nbaad … binaa kuch likhey enter press kar diya to multiword string 0 ho gaya…. aur condtion false ho gayi aur hum loop se
\nbahar aaa jaaengey.
\nJab hum Dos command se file read kartey hain … to carrriage return character add ho jata hai … lekin c program se nahi
\nhota …. isley c program se file open karney par uskaa size kam hotaa hai.<\/p>\n
Hum int float char bhi ek file mein enter kar saktey hain by using fprinf(variables se outpur lena) and
\nfscanf(variables mein store karna)<\/p>\n
Stdin ya stadard input lene ke baad humey enter key press ko fflush kar denaa chahiye … taki memory khali ho jaaey…<\/p>\n
Hum apne input ko directly print, display, port output pe daal saktey hain——–>stdprn,stdout,stdaux<\/p>\n
Numerical data ko binary format mein hi store karnaa chahiye…. kyonki agar char form mein karenge to ek char ek byte
\nlegaa aur jyaada space use hoga….. jabki binary format mein kam space use hogaa bits ki form mein storage distribute
\nhoga…..<\/p>\n
Agar text file mein humney 26 likha hai aur usey binar mein khol rahe hain …. to poori file nah khulegi kyonki 26 ko
\nEOF mana jaaegaa …. sahi kahaa naa<\/p>\n
BINARY FORMAT and STRUCTURES
\nfread
\nfwrite
\nfprintf
\nuse hotey hain<\/p>\n
&object se data fp pe fwrite kiya —-> bin
\n&object pe data fp se fread kiya —-> bin<\/p>\n
scanned data fp pe fprintf kiya ——> not a binary mode<\/p>\n
Ek file emp.dat mein agar ek record se doosre record pe jana hai to f(seek()); hotaa hai , start pe jana hai to rewind use hotaa
\nha … cursor postion dekni hai to ftell use hotaa hai……. reference point see_cur deta hai aur destination point
\n-recsize detaa hai.seek_set matlab start point<\/p>\n
LOW LEVEL mein hum read() close() open() buffer use kare hain with permissions to copy files on command line.<\/p>\n
Hum IO REDIRECTIONS ka use karke exe ka use bahut tareekon se kar saktey hain<\/p>\n
puneet.exe ek file hai jismey hum kuck stdin karaaengey aur wo VDU pe stdout hoga.compile karengey to exe generate hogee<\/p>\n
C:>Puneet.EXE < Source.c > Desination.c<\/p>\n
puneet.exe ka use hum source to destination file copy karney ke lie use kar rahey hain …. jabki wo is lie nahi banaai…
\nthis is called IO redirection<\/p>\n
Hish level languaage dos functions kaa group hai aur har DOS() func ROM_BIOS() functions se mil kar bana hai …. har
\nrom_bios function ka address Interrupt vector table mein store hotaa hai , aur ROM_BIOS input values inregs mein
\naur output values outregs registers mein store hotee hain in the low memory area of ROM.Inko hum change kar saktey hai
\naur virus kaa subroutine IVR mein daal saktey hain … heee hee hee aisaa mat karnaa …. mere bhai<\/p>\n
UNION:<\/p>\n
UNION MEIN hum ek memory space ko char int float mein share kartey hain alaag alag time pe.<\/p>\n
SHOWBITS<\/p>\n
yahan hum har cheez ko pahley left shift kartey hain aur phir right shift and then decimal nikaal lete hain….he hee hee<\/p>\n
AND bit ko switch off kar deta hai aur
\nOR bit ko switch on kar deta hai<\/p>\n
showbits function mein hum 1 ko 16 bit tak right shift kar kar kar har baar kisi bhi number jiskaa bin chahiye , ke saah AND
\nkaraatey hain aur hum wo bin number mil jata hai<\/p>\n
Enum se hum PERSON ko kai values , jaise married, unmarried ,divorsed de saktey hain ……<\/p>\n
Enum Person
\n{single, married,divorsed,widowed
\n};<\/p>\n
Enum Person person1,Person2;<\/p>\n
Typecasting mein hum kisi particular expression mein float ko int or int to float mein convert kar saktey hain<\/p>\n