%{
#include<stdio.h>
#include "y.tab.h"
%}
%%
[a-zA-Z0-9]+ { return NUM; }
[\n] return 0;
. return yytext[0];
%%
int yywrap()
{
return 1;
}
PROGRAM-YACC
%{
#include<stdio.h>
int flag=0;
%}
%token NUM
%left '+''-'
%left '*''/''%'
%left '('')'
%%
ArithmeticExpression:E{ printf("\nResult=%d\n",$$);return 0;}
;
E:E'+'E
|E'-'E
|E'*'E
|E'/'E
|E'%'E
|'('E')'
|NUM
;
%%
void main()
{
printf("\nEnter an arithmetic expression:\n");
yyparse();
if (flag==0)
printf("\nEntered arithmetic expression is Valid\n\n");
}
void yyerror()
{
printf("\nInvalid expression\n");
flag=1;
}

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