unix lab manual12

7/28/2019 Unix Lab Manual12

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1)Writeashellscriptthatacceptscommand lineargumentsandprintstheminreverseorder.

echo "Checking the number of arguments"

if [ $#then -eq 0 ]

echo "No argumentsexit

supplied"

fin=$#whiledo

[$n -gt 0 ]

eval echo \$$nn=`expr$n - 1`

done


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OUTPUT:

[root@localhost unix]$Checking the number ofNo arguments supplied

[root@localhost unix]$Checking the number ofgreatareindians

sh prg01.sharguments

sh prg01.sharguments indiansare great

[root@localhostunix]$
mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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2)Writeashellscript,whichtakestwofilenamesascommand linearguments

andchecks,whethertwofileshave identicalfilepermissionsandprint.Ifnot,

printfilenamesandtheirpermissionsseparately.

if [ $# -eq 0 ]thenechoexit

elif [thenechoexit

elseecho

fi

"No filename given"

$# -eq 1 ]

"Only one filename is given"

"Two filenames given"

if [ !thenechoexit

fi

-e $1-a ! -e $2 ]

"Bothfiles doesnot exist"

if [ !thenechoexit

fiif [ !thenechoexit

fi

-e $1]

"File1 does notexist"

-e $2]

"File2 does notexist"

x=`ls -l $1 | cut -c 2-10`y=`ls -l $2 | cut -c 2-10`

if [ $x = $y ]then

echoelseechoechoecho

fi

"Common permissions"

"Uncommon"File 1:""File 2:"

permissions"$x$y


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OUTPUT:

[mca3a6@localhost mca3a6]$sh prg2.shInsufficient number of arguments[root@localhost unix]$sh prg2.sh a1

only one file name is given,Insufficient[root@localhostunix]$[root@localhost unix]$sh prg2.sh f1f2TwoTwo

file names are givenfiles exists

Two file permissions are sameFile permission: rw-rw-r--[root@localhost unix]$chmod u+x f2[root@localhost unix]$sh prg2.sh f1Two file names are givenTwo files existsDifferent file permissionsFile1: rw-rw-r--File2: rwxrw-r--

f2

[root@localhostunix]$_
mailto:mca3a6@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:mca3a6@localhost


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3)Writeashellscripttocheckwhetherthegivenstringispalindromeornot.

echo "Enter a string:- "

read str

len=ècho $str | wc -c`

len=èxpr $len - 1`

i=1while [ $len -ge $i ]do

ch=ècho $str | cut -c $i`

ch1=ècho $str | cut -c $len`

if [ $ch != $ch1 ]thenecho "The given string is not a palindrome"exit

fi

len=èxpr $len - 1ì=èxpr $i + 1`

done

OUTPUT:

[mca3a6@localhost mca3a6]$ sh prg03.shEnter any stringmadamThe entered string is palindrome[mca3a6@localhost mca3a6]$ sh prg03.shEnter any stringsirThe string is not a palindrome[mca3a6@localhost mca3a6]$
mailto:mca3a6@localhostmailto:mca3a6@localhostmailto:mca3a6@localhostmailto:mca3a6@localhostmailto:mca3a6@localhostmailto:mca3a6@localhost


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4)Writeashellscripttodothefollowingactions:-

a) Accepttwofilenamesasanargument.b) Sortboththefilestotemporaryfileandmergethesortedfiletogetthe

finaloutput.Finallyremovethetemporaryfile.

if [ $# -ne 2 ]then

echo "Invalid arguments"exit

fi

sort $1>tempfile1sort $2>tempfile2

echo "Sorted Merged file is"

sort -m tempfile1 tempfile2 | sort -n

rm tempfile1 tempfile2

OUTPUT:

[root@localhost unix]$ sh file.shInvalid arguements

[root@localhost unix]$ sh file.sh mat

Invalid arguements122[[root@localhost unix]$ sh file.sh mat mat111 2 3224 5 67 8 9

[root@localhost unix]$ sh file.sh f1 f2hihow[root@localhost unix]$
mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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5)Writeashellscripttoacceptanumberandprintthedigitsofthatnumberinreverseorder.

echo "Enter a number: "

read numrev=0

if [ $num -lt 0 ]then

echo "Positive number has to be entered"

exitfi

while [ $num -gt 0 ]do

rem=èxpr $num % 10`rev=èxpr $rev \* 10 + $rem`num=èxpr $num \/ 10`

done

echo "The reverse of the given number is:"echo $rev

OUTPUT:

[root@localhost unix]$ sh prg04.shEnter a positive number6usage!Input atleast two digit number[root@localhost unix]$ sh prg04.shEnter a positive number56Reverse of the given number 56 is: 65[root@localhost unix]$


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6)Writeashellscriptto locktheterminal.

clear

echo "Enter your password"stty -echoread p1

stty echo

echo "Confirm your password: "stty -echoread p2

stty echoif [ "$p1" != "$p2" ]

thenecho "Confirmation mistake"exit

fi

clearecho "Screen locked"echo "To open the lock re-enter the password"stty -echoread p3

stty echo

while [ "$p3" != "$p1" ]do

echo "Wrong password"echo "Enter the password again"stty -echo

read p3stty echo

done

clearecho "Screen is unlocked"exit


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OUTPUT:

[root@localhost unix]$ sh terloc.shenter passwordconfirm password

confirmation mistake[root@localhost unix]$ sh terloc.shenter passwordconfirm passwordscreen lockedto open the lock , re-enter the passwordwrong passwordtry again re-enter the passwordscreen unlocked[root@localhost unix]$


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7)Writeashellscriptwhichacceptscommand lineargumentsandchecks

whetheritisavalidloginnameornot.Ifitisvalid,printthe loginnameand

homedirectory.

if [ $# -eq 0 ]then

echo "No arguments"exit

elsefor x in $*do

if grep "^$x:" /etc/passwd>tempthen

y=`cut -d ":" -f 6 temp`echo "Login name= " $x

echo "Home directory= " $yelseecho "Login name does not exist"

fidone

fi

OUTPUT:

[root@localhost unix]$ sh prg05.sh

No arguments[root@localhost unix]$ sh prg05.sh mca3a10LOGIN NAME:= mca3a10DIR NAME:= /home/mca3a10[root@localhost unix]$ sh prg05.sh mcaLogin doesnt exist[root@localhost unix]$
mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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OUTPUT:

[root@localhost unix]$ sh links.sh 123123 does not exist[root@localhost unix]$ sh links.sh p.sh

ls: file: No such file or directorylinks.sh: [: -eq: unary operator expectedFile has links/home/mca3a6/p.sh/home/mca3a6/q.sh/home/mca3a6/r.sh[root@localhost unix]$ sh links.sh prg02.shprg02.sh does not exist[root@localhost unix]$


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currentmonthcalendar inwhichtodays9)Writeashellscripttodisplaydateisreplacedby*or**.

#!bin/basha=`date +%e`

if [ $a -lt 10 ]then

cal|sed "s/$a/*/"else

cal|sed "s/$a/**/"fi

OUTPUT:

[root@localhost unix]$ sh prg10.shNovember 2007Su Mo Tu We Th Fr Sa

1 2 34 5 6 7 8 9 10

11 12 13 ** 15 16 1718 19 20 21 22 23 2425 26 27 28 29 30

[root@localhost unix]$
mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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10)WriteanAWKshell scriptthatfolds longline intonewcolomns.Thus

any linethatexceeds5charactersmustbebroken intoafter5thCharacter

and / beappendedasan indicationoffoldingandprocessingistobe

continuedwithresidue.

awk '{str=$0while(length(str)>5){printf("%s\\\n",substr(str,1,5))str=substr(str,6,length(str)-5);

}print str} ' $@

OUTPUT:

[root@localhost unix]$ sh prg11.shall the students in our college read well told the teacherall t\he st\udent\s in \our c\olleg\

e rea\d wel\l tol\d the\teac\her

mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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11)WriteanAWKprogramtofindthetransposeofagivenmatrix.

BEGIN{j=0printf("Entered matrix is\n")

}{for(i=1;i


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OUTPUT:

[root@localhost unix]$ awk -f prg8.awk mat1Entered matrix is

1

47

2 3

5 68 9Transpose of matrix is

12

3

4 75 8

6 9[root@localhost unix]$ cat>mat21040

70

20 3050 60

80 90[root@localhost unix]$ cat mat2

1040

70

20 3050 60

80 90[root@localhost unix]$ awk -f prg8.awk mat2Entered matrix is104070

20 3050 6080 90

Transpose of matrix is102030

40 7050 8060 90

mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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12)Writeashell programwhichacceptscommand lineargumentandcreates

directorisinhierarchical order.

if [ $# -eq 0 ]then

echo "Insufficient Arguments"exit

fiIFS=`/`for dirname in $*domkdir $dirnamecd $dirname

done

OUTPUT:

[root@localhost unix]$ sh prg9.shInsufficient Arguments[root@localhost unix]$ sh prg9.sh bangalore/rnsit/mca[root@localhost unix]$ cd bangalore

[root@localhostbangalore]$ lsrnsit[root@localhostbangalore]$ cd rnsit[root@localhost rnsit]$ ls

mca[root@localhost rnsit]$
mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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1. WriteaLEXprogramtocountnumberofblankspaces,characters,

lines,wordsfromagiventext.

%{int bcount=0,ccount=0,lcount=0,wcount=0;

%}%%[^ \t\n]+ {wcount++;ccount+=yyleng;}\n { lcount++; }" " { bcount++;ccount;}. {ccount++; }

%%

main(){printf("Enter the text");

yylex();printf("word=%d\n char=%d\n line=%d\n blankspace=%d\n",wcount,ccount,lcount,bcont);}OUTPUT:[root@localhost unix]$ lex lex1.l[root@localhost unix]$ cc lex.yy.c -ll[[root@localhost unix]$./a.outEnter the text

this is linux red hat enterpise asword=8

char=35line=2blankspace=8[root@localhost unix]$

version


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2. WriteaLEXprogramtocountnumberofpositiveandnegative

integersandfractions.%{int pint=0,nint=0,pfr=0,nfr=0;%}

%%\+?[0-9]+-[0-9]+

{pint++;}{nint++;}

\+?[0-9]*\.[0-9]+ {pfr++;}-[0-9]*\.[0-9]+ {nfr++;}. {}%%main(){printf("Enter the no.: ");yylex();

printf("pos int=%d\n neg int=%d",pint,nint);printf("pos frac=%d\n neg frac=%d",pfr,nfr);}

OUTPUT:

[root@localhostunix]$lexlex2.l[root@localhostunix]$cclex.yy.c-ll[root@localhostunix]$./a.outEnter the no.: 5

7

8

-43

-45

-44.6

-7.3

7.8

4.8

pos int=3neg int=2pos frac=2neg frac=2

[mca3a5@localhost mca3a5]$
mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:mca3a5@localhostmailto:mca3a5@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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3. WriteaLEXprogramtocheckwhetherthegivenarithmeticalexpressionisvalidornotandprintnumberofoperatorsandoperands.

%{

int flag=1;

int oprc=0,digic=0,top=-1;char stack[10];

%}

digit [0-9]+opr[+*/-]

%%

['('] {stack[++top]='(';}[')'] {flag=1;

if((stack[top]!='(') && (top!=-1)){printf("INVALID EXPRN\n");exit(0);

}

top--;}

{digit} {digic++; }{opr}/{digit} {oprc++; }{opr}/['('] {oprc++; }

. { printf("INVALID");exit(0);}%%

main(){

yylex();if(((oprc+1 == digic)||(oprc == digic)) && (top == -1)){

printf("VALID EXPRN\n");printf("NUMBER OF OPERATORS : %d\nNUMBER OF OPERANDS :

%d",oprc

digic);}else{

printf("INVALID EXPN");}

}


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OUTPUT:[root@localhostunix]$lex lexexprn.l[root@localhostunix]$cc lex.yy.c -ll[root@localhostunix]$./a.out(3+1)

VALID EXPRNNUMBER OF OPERATORS : 1NUMBER OF OPERANDS : 2[mca3a8@localhost mca3a8]$ ./a.out3*%INVALID

mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:mca3a8@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:mca3a8@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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4. WriteaLEXprogramtocheckwhetheragivensentenceissimpleor

compound.%{

int flag=0;%}

%%and flag=1;or flag=1;but flag=1;

%%

main(){

yylex();if(flag)

{ printf("ITS A COMPUND STATEMENT\n");}else{

printf("ITS A SIMPLE STATEMENT");}

}

OUTPUT:

[root@localhostunix]$lex lexsimp.l[root@localhostunix]$cc lex.yy.c -ll[root@localhostunix]$./a.outme and my friend went to the marketme my friend went to the marketITS A COMPUND STATEMENT

[root@localhostunix]$./a.outI am a writerI am a writerITS A SIMPLE STATEMENT

mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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5. WriteaLEXprogramtocountnumberofprintfandscanffroma

givencprogramfileandreplacethemwithwriteandreadrespectively.

%{

int pcount=0,scount=0;%}

%%

printf {pcount++,fprintf(yyout,"write ");}scanf {scount++,fprintf(yyout,"read ");}

%%

main()

{yyin = fopen("dee.c","r");yyout = fopen("dee2.c","w");yylex();printf("NUMBER OF PRINTF = %d\n NUMBER OF SCANF =

%d",pcount,scount);}

OUTPUT:

[root@localhostunix]$lex lexcountpfsf.l

[root@localhostunix]$cc lex.yy.c -ll[root@localhostunix]$./a.outNUMBER OF PRINTF = 2NUMBER OF SCANF = 1[mca3a8@localhost mca3a8]$ cat dee2.c#include(stdio.h)main()

{int a,b;write ("ENTER 2 NUM\n");

read ("%d %d",&a,&b);write ("SUM = %d",a+b);

}

mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:mca3a8@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:mca3a8@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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6. WriteaLEXprogramtocountnumberofvowelsandconsonants.

%{int vow=0;int con=0;

%}

%%[aeiouAEIOU] {vow++;}[a-zA-Z] {con++;}%%

main(){

printf("enter the string\n");yylex();

printf("\n the number of vowels in a string is %d \n",vow);printf("\n the number of consonents in a string is %d \n",con);}

OUTPUT:

[root@localhost unix]$ lex vowcons.l[root@localhost unix]$ cc lex.yy.c -ll[root@localhost unix]$ ./a.outenter the stringhello friends do unix programs its interesting.

.

the number of vowels in a string is 14

the number of consonents in a string is 26[root@localhost unix]$


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1. WriteaYACCprogramtorecognizethegrammer[anb/n>0].Test

whetherthefollowingstringbelongstothisgrammer.%{

#include

%}

%token a b

%%st:st reca endb '\n' {printf("STRING BELONGS TO GRAMMER");}||error '\n'{yyerror("DOES NOT BELONG TO GRAMMER");yyerrok;}reca:enda reca

|;

enda:a;endb:b;

%%

main(){ printf("Enter the text :");

yyparse();}yylex(){

char c;while((c=getchar())==' ');if(c=='a')return a;if(c=='b')return b;

return c;}

yyerror(char *s){

printf("%s",s);}


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OUTPUT:[root@localhost unix]$ yacc -d yacc1.y[root@localhost unix]$cc y.tab.c -ll[root@localhost unix]$ ./a.outEnter the text :a

syntax errorDOES NOT BELONG TO GRAMMERbSTRING BELONGS TO GRAMMERaaaaabSTRING BELONGS TO GRAMMERbasyntax errorDOES NOT BELONG TO GRAMMER



28/35

2. writeaYACCprogramtorecognizethegrammer[a

nbn/n>0].

#include%{

%}

%token a b

%%st:st reca endb '\n'{printf("STRING BELONG TO GRAMMAR ");}|st'\n'{printf("WHR N VALUE IS 0");}||error '\n'{yyerror("DOES NOT BELONG TO THE GRAMMAR");yyerrok;}

;reca:enda reca endb|endaenda:a;

endb:b;

%%

main(){

printf("Enter the text :");yyparse();

}yylex(){

char c;while((c=getchar())==' ');if(c=='a') return a;if(c=='b') return b;return c;

}

yyerror(char *s){

printf("%s",s);}


29/35

OUTPUT:[root@localhost unix]$ yacc yacc2.y[root@localhost unix]$ cc y.tab.c -ll[root@localhost unix]$ ./a.outEnter the text :aab

syntax errorDOES NOT BELONG TO THE GRAMMARaabbSTRING BELONG TO GRAMMAR abvsyntax errorDOES NOT BELONG TO THE GRAMMARabSTRING BELONG TO GRAMMAR baasyntax errorDOES NOT BELONG TO THE GRAMMARWHR N VALUE IS 0



30/35

3. writeaYACCprogramtoevaluateanarithmeticexpression.%{

#include#include#include

#include#define YYSTYPE double%}%token num%left '+' '-'%left '*' '/'%%st: st expr '\n' {printf("value is = %f \n",$2);}

|st '\n'||error '\n' {printf("invalid\n");}

;expr: num {$$=$1;}|expr '+' expr {$$=$1+$3;}|expr '-' expr {$$=$1-$3;}|expr '*' expr {$$=$1*$3;}|expr '/' expr {

if($3==0){

printf("division by zero!\n");exit(0);

}else$$=$1/$3;

}|'(' expr ')';

%%main(){

printf("enter an expression to evaluate:");yyparse();

}yylex()

{int ch;while((ch=getchar())==' ');if(isdigit(ch)|ch=='.'){

ungetc(ch,stdin);scanf("%lf",&yylval);


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return num;

}return ch;

}yyerror(char *s)

{ printf("%s",s);}


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OUTPUT:

[root@localhostyacc]$ yacc expr.y[root@localhostyacc]$ cc y.tab.c -ll

[root@localhostyacc]$ ./a.outenter an expression to evaluate:4+5*7value is = 39.000000

[root@localhostyacc]$ ./a.outenter an expression to evaluate:6/4value is = 1.500000

[root@localhostyacc]$ ./a.outenter an expression to evaluate:9/0division by zero!

[root@localhostyacc]$

4. writeaYACCprogramwhichrecognizesavalidvariablewhichstartswithletterfollowedbyadigit.

%{#include#include

%}

%token let dig

%%sat:let recld '\n'{printf("ACCEPTED\n");exit(0);}

|let '\n' {printf("ACCEPTED\n");exit(0);}||error '\n' {printf("INVALID");yyerrok;exit(0);}
mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


33/35

;

recld:let recld|dig recld|let|dig

;

%%

yylex(){

char ch;while((ch=getchar())==' ');if(isalpha(ch))

return let;if(isdigit(ch))

return dig;return ch;

}

yyerror(char *s){

printf("%s",s);

}

main(){

printf("ENTER THE STRING\n");yyparse();

}

OUTPUT:

[root@localhostyacc]$ yacc yacc4.y[root@localhostyacc]$ cc y.tab.c -ll[root@localhostyacc]$ ./a.out

ENTER THE STRINGa4ACCEPTED

[root@localhostyacc]$ ./a.outENTER THE STRING7er

syntax errorINVALID[root@localhostyacc]$ ./a.outENTER THE STRING
mailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhostmailto:root@localhost


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$l

syntax errorINVALID[root@localhostyacc]$ ./a.outENTER THE STRINGsumACCEPTED

[root@localhostyacc]$

5. writeaYACC&LEXprogramto identifyvalid ifandif-elsestatement.

LEXPROGRAM:-%{

#include#include#include"y.tab.h"

%}

%%if return IF;else return ELSE;[a-zA-Z0-9+\-\*/=]+ return STAT;[a-zA-Z0-9+\-\*/=&!]+ return CONDITION;. return yytext[0];%%

YACCPROGRAM:-%{

int v=1;

%}%token IF STAT CONDITION ELSE%nonassoc IF%nonassoc ELSE

%%ifstruct: IF expr state1

|IF expr state1 ELSE state1 %prec ELSE;

state1: stmt|"{"state"}"

|ifstruct %prec IF;

state: stmt|stmt state|ifstruct|ifstruct state;

expr: "("CONDITION")"|"("STAT")"


35/35

;

stmt: STAT ";"|";";

%%

int yyerror(char *s){v=0;

}

main(){

yyparse();if(v)

printf("valid");else

printf("invalid");}

OUTPUT:

[root@localhostyacc]$lexlex55.l[root@localhostyacc]$yacclex55.y[root@localhostyacc]$cclex.yy.cy.tab.c-ll[root@localhostyacc]$./a.outENTERTHEIF-ELSESTATEMENTif(a>b)

big=a;

else

big=b;

valid[root@localhostyacc]$./a.outENTERTHEIF-ELSESTATEMENT

if(a

unix lab manual12

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