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--------------------------------------------INDEX---------------------------------------------------------------------------


EXP3 - 15
EXP 4 - 46
EXP 5 - 83
EXP 6 - 109
EXP 7 - 178
EXP 8 - 242




--------------------------------------------------------------------------- experiment 3 --------------------------------------------------------------------------------------


%{

#include<stdio.h>
int chars = 0;
int word = 0;
int space = 0;
int lines = 0;

%}

%%

[^ \n\t]+ {word++,chars+=yyleng;}
\t {space++;}
" " {space++;}
\n {lines++;}

%%

int yywrap(){ return 1; }

void main(){

	yylex();
	printf("char: %d\nword: %d\nspace: %d\nlines: %d\n", chars,word,space,lines);	
	}
  
  
---------------------------------------------------------------------------------------exp4-----------------------------------------------------------------------------
  
  %{

#include<stdio.h>
#include<string.h>
int i;

%}

%%

[a-z A-Z]* {

	for(i=0;i<=yyleng;i++){

		if((yytext[i]=='a')&&(yytext[i+1]=='b')&&(yytext[i+2]=='c')){
			
			yytext[i]='A';
			yytext[i+1]='B';
			yytext[i+2]='C';}}
			
	printf("%s",yytext);
	}

[\t]* return 0;
.* {ECHO;}
\n {printf("%s",yytext);}

%%

void main(){
yylex();}

int yywrap(){
return 1;}

---------------------------------------------------------------------------------------------exp5------------------------------------------------------------------------------------

%{

#include<stdio.h>
int vow=0,con=0;

%}

%%

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

%%

int main(){
	printf("Enter input string... at end press ^d :\n");
	yylex();
	printf("Number of vowels=%d\n",vow);
	printf("Number of consonants=%d\n",con);
	}

int yywrap() {return 1;}


------------------------------------------------------------------------------------------------exp6-------------------------------------------------------------------------------------------------

-----lex-----

%{
#include "y.tab.h"
%}

%%

[a-zA-Z_][a-zA-Z_0-9]* return id;
[0-9]+(\.[0-9]*)? return num;
[+/*]      return op;
.          return yytext[0];
\n         return 0;

%%

int yywrap()
{
return 1;
}


-----yacc-------

%{

#include<stdio.h>
int valid = 1;

%}

%token num id op

%%

start : id '=' s ';'
s: id x
| num x
| '-' num x
| '(' s ')' x
;
   
x: op s
| '-'s
|
;
   
%%

int yyerror(){

	valid=0;
	printf("\nInvalid expression!\n");
	return 0;

	}

int main(){

	printf("\nEnter the expression:\n");
	yyparse();
	
	if(valid){
		printf("\nValid expression!\n");}
		
	}
  
  ------------------------------------------------------------------------------------------------------exp7-----------------------------------------------------------------------------------
  -----------lex------------------
  %{

#include "y.tab.h"

%}

%%

[a-zA-Z_][a-zA-Z_0-9]*	return letter;
[0-9]			return digit;
.			return yytext[0];
\n			return 0;

%%

int yywrap()
{
return 1;
}

--------yacc-----------

%{

#include<stdio.h>
int valid = 1;

%}

%token digit letter
%%
start : letter s

s :	letter s

	| digit s
	
	|
	;
	
%%

int yyerror()
{
	printf("\nIts not an identifier!\n");
	valid=0;
	return 0;
	
}

int main()

{
	printf("\nEnter a string: ");
	yyparse();
	if(valid)
	{
		printf("\nIt is an identifier!\n");
	}
}


-----------------------------------------------------------------------------------exp8-------------------------------------------------------------------------------------------------------------
	
-------lex------------
%{
#include<stdio.h>
#include "y.tab.h";
extern int yylval;
%}

%%
[0-9]+ {
yylval=atoi(yytext);
return NUMBER;
	}
[\t];
[\n] return 0;
. return yytext[0];

%%

int yywrap(){
return 1;
}

	
	
-----yacc-------

%{
#include<stdio.h>
int flag=0;
%}
%token NUMBER
%left '+''-'
%left '*' '/' '%'
%left '(' ')'

%%

ArithemeticExpression: E{
printf("\nResult=%d\n",$$);
return 0;
}; 
E:E'+'E{$$=$1+$3;}
E:E'-'E{$$=$1-$3;}
E:E'*'E{$$=$1*$3;}
E:E'/'E{$$=$1/$3;}
E:E'%'E{$$=$1%$3;}
|'('E')' {$$=$2;}
| NUMBER {$$=$1;}
;

%%

void yyerror()
{
printf("\n ENTER THE ARITHEMATIC EXPRESSION IS INVALID\n\n");
flag=1;
}

void main()
{
printf("\n ENTER THE ARITHEMATIC EXPRESSION:\n");
yyparse();
if(flag==0)
printf("\n ENTER THE ARITHEMATIC EXPRESSION IS VALID\n\n");
}