11. Program in YACC to recognize the language (a^n b , n>=10). (output to say input is valid or not)

 

Program in YACC to recognize the language (a^n b , n>=10). (output to say input is valid or not)



File Name : pr12.y
/* program to check whether the given string is  a part of the language a^n b or not */
/* Shows nothing if string is a part of language */
/* shows a message if string is not a part of language */
%{
 #include<stdio.h>
 int yylex(void);
 int yyerror(char *);
 
%}

%token A B   //tokens : the alphabets of language 'a' and 'b' 

%%
//production rules for grammar
expr: s B         
  ;
s : s A 
| A   

;

%%

int main()
{
 
 printf("Enter the string \n");
 yyparse(); 
 return 0;
}

int yyerror(char *s)
{
 printf("Invalid: Not a part of the language - a^n b \n");
}


File Name : pr12.l
%{
 #include "y.tab.h"
 extern int yylval;
%}
A [a]
B [b]
%%

{A} {yylval=yytext[0];return A;}
{B} {yylval=yytext[1];return B;}
\n {return 0;}
. {return yytext[0];}

%%




// Output of the Above Program.

Program in YACC to recognize the language (a^n b , n>=10). (output to say input is valid or not)
Program in YACC to recognize the language (a^n b , n>=10). (output to say input is valid or not)






































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