%{
/* This LEX program returns the tokens for the expression */
#include "y.tab.h"
%}
%%
"=" {printf("\n Operator is EQUAL");}
"+" {printf("\n Operator is PLUS");}
"-" {printf("\n Operator is MINUS");}
"/" {printf("\n Operator is DIVISION");}
"*" {printf("\n Operator is MULTIPLICATION");}
[a-zA-Z]*[0-9]* {
printf("\n Identifier is %s",yytext);
return ID; }
. return yytext[0];
\n return 0;
%%
int yywrap()
{
return 1;
}
Program name:ex3.y
%{
#include<stdio.h>
/* This YACC program is for recognizing the Expression */
%}
%token A ID
%%
statement: A'='E
| E {
printf("\n Valid arithmetic expression");
$$=$1;
}
;
E: E'+'ID
| E'-'ID
| E'*'ID
| E'/'ID
| ID
;
%%
extern FILE*yyin;
main() {
do {
yyparse();
}while(!feof(yyin)); }
 yyerror(char*s)
{
}

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